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{{Short description|Portion of the atmosphere controlled by a country}}
{{Short description|Portion of the atmosphere controlled by a country}}
{{Distinguish|Aerospace|Outer space}}
{{Distinguish|Aerospace}}
{{Globalize|article|USA|2name=the United States|date=May 2017}}
{{Use dmy dates|date=September 2019}}
{{Use dmy dates|date=September 2019}}


'''Airspace'''<ref>{{cite web |url=http://www.faraim.org/aim/aim-4-03-14-129.html |title=AIM Chapter 3. Airspace |url-status=dead |archive-url=https://web.archive.org/web/20140607005739/http://www.faraim.org/aim/aim-4-03-14-129.html |archive-date=7 June 2014}}</ref> is the portion of the atmosphere controlled by a [[country]] above its territory, including its [[territorial waters]] or, more generally, any specific three-dimensional portion of the atmosphere.<ref>{{cite book|title=A Dictionary of Aviation |first=David W. |last=Wragg |isbn=0-85045-163-9 |publisher=Frederick Fell, Inc. |publication-place=New York |date=1974 |edition=1st American |page=29}}</ref>  It is not the same as [[outer space]] which is the expanse or space outside the Earth and [[aerospace]] which is the general term for Earth's atmosphere and the outer space within the planet's vicinity.
{{Use British English|date=October 2025}}
History:


== History for the Karman Line ==
[[File:FIR France.svg|thumb|[[Flight information region|Flight information regions]] in [[France]]]]
Until the middle of the 20th century, which was considered the pioneering time of aviation, there were no fixed boundaries as to what was national airspace and when it became international airspace. Because of this, a kind of customary law applied at the time and most countries such as the United Kingdom or the United States considered airspace as international from about 13,000 feet. However, this only applied in times of peace and if it was to the advantage of the states, there was no clear demarcation of the airspace question until the 1950s when the Karman Line was defined, which is why an international time was assumed.
'''Airspace''' is the portion of the [[Atmosphere of Earth|atmosphere]] controlled by a [[country]] above its territory and [[territorial waters]] that fall under the country's sovereignty and regulatory control.  


Within the United States:
Internationally, allocation and management of airspace is coordinated by the [[International Civil Aviation Organization]] (ICAO), which was established through the Chicago Convention in 1947 to unify air traffic. ICAO organizes airspace into [[Flight information region|Flight Information Regions]] (FIRs) and provides classification guidelines. National authorities, such as the [[Federal Aviation Administration|FAA]], [[Civil Aviation Authority (United Kingdom)|CAA]], or [[European Union Aviation Safety Agency|EASA]] implement rules and regulations for [[air traffic control]], [[Special use airspace|special-use airspace]], and enforcement within their own FIRs.
* [[Controlled airspace]]<ref>{{cite web |url=http://www.faraim.org/aim/aim-4-03-14-131.html |title=AIM Section 2. Controlled Airspace |url-status=dead |archive-url=https://web.archive.org/web/20140607010704/http://www.faraim.org/aim/aim-4-03-14-131.html |archive-date=7 June 2014 }}</ref> exists where it is deemed necessary that [[air traffic control]] has some form of positive executive control over aircraft flying in that airspace (however, air traffic control does not necessarily control traffic operating under [[visual flight rules|visual flight rules (VFR)]]<ref>{{cite web |url=http://www.faraim.org/aim/aim-4-03-14-707.html |title=Pilot/Controller Glossary – VISUAL FLIGHT RULES |url-status=dead |archive-url=https://web.archive.org/web/20141218033959/http://www.faraim.org/aim/aim-4-03-14-707.html |archive-date=18 December 2014}}</ref> within this airspace).


Airspace may be further subdivided into a variety of areas and zones, including those where there are either restrictions on flying activities or complete prohibition of flying activities.
Airspace can be used for both [[Civil aviation|civilian flight]] and for defense or military operations, and countries are responsible for protecting their own airspace using measures such as [[Quick Reaction Alert|air policing.]] Legal and technical challenges include the vertical boundary between airspace and outer space and temporary restrictions such as [[NOTAM|NOTAMs]] or [[Temporary Flight Restriction|TFRs]].


[[File:Airspace classes (United States).png|thumb|500px|Airspace classes in the United States]]
== Legal framework and ownership ==
On 4 April 1947, the [[International Civil Aviation Organization]] (ICAO) was established through the [[Convention on International Civil Aviation|Chicago Convention]], aimed at unifying and coordinating international air travel.<ref name="icao-convention">{{cite web |title=Convention on International Civil Aviation |url=https://www.icao.int/publications/pages/doc7300.aspx |access-date=5 June 2021 |publisher=International Civil Aviation Organization |id=Doc 7300}}</ref> ICAO provides regulations and guidance for countries concerning air navigation, its infrastructure, [[flight inspection]], prevention of unlawful interference, and facilitation of border-crossing procedures for international [[civil aviation]].<ref>{{cite book |last=Wragg |first=David W. |title=A Dictionary of Aviation |publisher=Osprey |year=1973 |isbn=9780850451634 |edition=first |page=165}}</ref>


==Horizontal boundary==
Sovereign airspace refers to airspace owned by a country. By law, a country has the right to airspace above its land and waters up to 12 miles from their coast (if present). Beyond 12 miles, airspace is considered international.<ref>{{Cite web |title=Understanding airspace {{!}} UK Civil Aviation Authority |url=https://www.caa.co.uk/commercial-industry/airspace/airspace-change/understanding-airspace/ |access-date=2025-10-01 |website=www.caa.co.uk}}</ref> ICAO divides airspace into [[Flight information region|Flight Information Regions (FIR)]] which are sections of airspace dedicated to a specific country. A country is responsible, within its own FIR(s), to provide air traffic control services and regulation for flight.<ref name=":3">{{Cite web |title=Air Traffic Control Service {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/air-traffic-control-service |access-date=2025-10-01 |website=skybrary.aero}}</ref><ref name=":4">{{Cite web |title=Flight Information Region (FIR) {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/flight-information-region-fir |access-date=2025-10-01 |website=skybrary.aero}}</ref> This is usually done using a national regulator, such as the [[Federal Aviation Administration|FAA]], [[Civil Aviation Authority (United Kingdom)|CAA]], or [[European Union Aviation Safety Agency|EASA]], which are able to create their own regulations while still abiding by ICAO guidelines.<ref>{{Cite web |title=Convention on International Civil Aviation |url=https://treaties.un.org/doc/publication/unts/volume%2015/volume-15-ii-102-english.pdf |access-date=1 October 2025 |website=UN |page=6}}</ref> Some countries may have multiple FIRs, for example, the United States has sole jurisdiction in 24 FIRs.<ref>{{Cite web |date=5 November 2013 |title=Current FIR Status |url=https://www2023.icao.int/safety/FITS/Lists/Current%20FIR%20Status/Exort%20to%20excel.aspx#InplviewHash10605b1c-0271-4939-82e9-03ca84139646=SortField%3DLocation%255fx0020%255fIndicator-SortDir%3DAsc |access-date=12 August 2025 |website=[[ICAO]]}}</ref>  A country may, by international agreement, assume responsibility for providing [[Air traffic control|air traffic control services]] in parts of international airspace, which then becomes part of their FIR.<ref>{{cite web |title=The Legal Principles Governing the Control of National Airspace and Flight Information Regions and their Application to the Eastern Mediterranean |url=https://erpic.org/wp-content/uploads/2017/02/the-legal-principles-governing-the-control-of-national-airspace-and-flight-information-regions-and-their-application-to-the-eastern-mediterranean-2009.pdf |url-status=live |archive-url=https://web.archive.org/web/20190621091927/https://erpic.org/wp-content/uploads/2017/02/the-legal-principles-governing-the-control-of-national-airspace-and-flight-information-regions-and-their-application-to-the-eastern-mediterranean-2009.pdf |archive-date=21 June 2019 |access-date=21 June 2019}}</ref> Certain FIRs are dedicated oceanic sectors which support and control air traffic crossing large oceans such as the [[Atlantic Ocean|North Atlantic]], which is made up of 7 FIRs controlled by countries like the [[United Kingdom|UK]], [[Republic of Ireland|Ireland]], and [[Canada]].<ref>{{Cite web |title=North Atlantic Operations - Airspace |url=https://skybrary.aero/articles/north-atlantic-operations-airspace |access-date=2025-11-01 |website=skybrary.aero}}</ref>
[[File:US Overflight Fee Map.png|thumb|upright=2|alt=Map of approximately the Northern Hemisphere from Japan & New Guinea (left edge) to the middle of North Atlantic Ocean. The map shows yellow over the continental U.S. and Bahamas, Alaska (and much of the Bering Sea), and a yellow circle around Bermuda. Most of the Northern Pacific is colored blue along with a small section in the middle of the Gulf of Mexico, and the western half of the North Atlantic from roughly the latitude of Maine to the northern edge of the Leeward Islands (or Puerto Rico).|The [[Federal Aviation Administration]] (FAA) of the United States provides air traffic control services over U.S. territory and over international waters where it has been delegated such authority by the [[International Civil Aviation Organization]]. This map depicts [[Freedoms of the air#First freedom|overflight]] fee regions. The yellow regions are where the U.S. provides ''enroute'' ATC services (mostly over land territory). The blue regions are where the U.S. provides ''oceanic'' ATC services over international waters.]]


By international law, a state "has complete and exclusive sovereignty over the airspace above its territory", which corresponds with the maritime definition of [[territorial waters]] as being 12 nautical miles (22.2&nbsp;km) out from a nation's coastline.<ref>{{cite web | url=https://www.icao.int/publications/Documents/7300_cons.pdf | access-date=21 June 2019 | title=Convention on an International Civil Aviation }}</ref> Airspace not within any country's territorial limit is considered international, analogous to the "[[International waters|high seas]]" in maritime law.
There is no international agreement on the vertical extent of sovereign airspace,<ref name="Harris & Harris 2006">{{cite journal |last1=Harris |first1=Alexandra |last2=Harris |first2=Ray |date=2006 |title=The need for air space and outer space demarcation |journal=Space Policy |volume=22 |issue=1 |pages=3–7 |bibcode=2006SpPol..22....3H |doi=10.1016/j.spacepol.2005.11.004}}</ref> although most countries use the [[Kármán Line]], 100km (62mi), as the legal distinction between airspace and outer space.<ref name="Byers & Boley 2021">{{cite book |last1=Byers |first1=Michael |url=https://www.cambridge.org/core/books/who-owns-outer-space/960CCB0464744F845B09434D932699EC |title=Who Owns Outer Space?: International Law, Astrophysics, and the Sustainable Development of Space |last2=Boley |first2=Aaron |date=2022 |publisher=Cambridge University Press |isbn=9781108597135 |page=13}}</ref><ref>{{Cite news |date=2015-09-24 |title=Who owns outer space? |url=https://www.bbc.com/news/science-environment-34324443 |access-date=2025-10-01 |work=BBC News |language=en-GB}}</ref><ref name="Dr. S. Sanz Fernández de Córdoba">{{cite web |last=Sanz Fernández de Córdoba |first=Dr. S. |date=2004-06-24 |title=The 100&nbsp;km Boundary for Astronautics |url=https://www.fai.org/page/icare-boundary |access-date=28 December 2020 |publisher=Fédération aéronautique internationale}}</ref> However, descending [[Space Shuttle]]s flew closer than {{convert|80|km|0|abbr=on}} over other nations, such as Canada, without requesting permission first.<ref>{{cite web |last=White |first=Robert E. |title='Space Weapons Ban: Thoughts on a New Treaty |url=http://inesap.org/bulletin20/bul20art08.htm |archive-url=https://web.archive.org/web/20080515202422/http://www.inesap.org/bulletin20/bul20art08.htm |archive-date=15 May 2008 |access-date=27 July 2007}}</ref>[[File:US Overflight Fee Map.png|thumb|upright=2|alt=Map of approximately the Northern Hemisphere from Japan & New Guinea (left edge) to the middle of North Atlantic Ocean. The map shows yellow over the continental U.S. and Bahamas, Alaska (and much of the Bering Sea), and a yellow circle around Bermuda. Most of the Northern Pacific is colored blue along with a small section in the middle of the Gulf of Mexico, and the western half of the North Atlantic from roughly the latitude of Maine to the northern edge of the Leeward Islands (or Puerto Rico).|The [[Federal Aviation Administration]] (FAA) of the United States provides air traffic control services over U.S. territory and over international waters where it has been delegated such authority by the [[International Civil Aviation Organization]]. This map depicts [[Freedoms of the air#First freedom|overflight]] fee regions. The yellow regions are where the U.S. provides ''enroute'' ATC services (mostly over land territory). The blue regions are where the U.S. provides ''oceanic'' ATC services over international waters.]]


However, a country may, by international agreement, assume responsibility for controlling parts of international airspace, such as those over the oceans. Such airspace in respect of which a country is responsible under the [[International Civil Aviation Organization]] (ICAO) for operational control is called a [[Flight information region|Flight Information Region]] (FIR). For a coastal state, the FIR consists of the airspace above its land and sea territory plus any international airspace in respect of which ICAO has assigned responsibility to that state.<ref>{{cite web | url=https://erpic.org/wp-content/uploads/2017/02/the-legal-principles-governing-the-control-of-national-airspace-and-flight-information-regions-and-their-application-to-the-eastern-mediterranean-2009.pdf | access-date=21 June 2019 | title=The Legal Principles Governing the Control of National Airspace and Flight Information Regions and their Application to the Eastern Mediterranean }}</ref>
=== Private air rights ===
 
For instance, the United States provides air traffic control services over a large part of the Pacific Ocean, even though the airspace is international.
 
==Vertical boundary==
There is no international agreement on the vertical extent of sovereign airspace,{{citation needed|date=June 2019}} with suggestions ranging from about {{convert|30|km|0|abbr=on}}—the extent of the highest aircraft and balloons—to about 160 km (100 mi)—approximately the lowest extent of short-term stable orbits.  (The satellite Lixing-1 had a stable orbit with an apogee of 140 km (87 mi) for three days.)<ref>{{Cite web|url=https://space.skyrocket.de/doc_sdat/lixing-1.htm|title=Lixing 1}}</ref> The [[Fédération Aéronautique Internationale]] has established the [[Kármán line]]—at an altitude of {{convert|100|km|0|abbr=on}}—as the boundary between the Earth's atmosphere and [[outer space]],<ref name="Dr. S. Sanz Fernández de Córdoba">{{cite web |first=Dr. S. |last=Sanz Fernández de Córdoba |date=2004-06-24 |title=The 100&nbsp;km Boundary for Astronautics |url=https://www.fai.org/page/icare-boundary |access-date=28 December 2020 |publisher=Fédération aéronautique internationale }}</ref> while the United States considers anyone who has flown above {{convert|80|km|mi}} to be an [[astronaut]] {{citation needed|date=August 2021}}. Indeed, descending [[Space Shuttle]]s flew closer than {{convert|80|km|0|abbr=on}} over other nations, such as [[Canada]], without requesting permission first.<ref>{{cite web | url=http://inesap.org/bulletin20/bul20art08.htm| archive-url=https://web.archive.org/web/20080515202422/http://www.inesap.org/bulletin20/bul20art08.htm | archive-date=15 May 2008 | access-date=27 July 2007 |last=White | first= Robert E | title='Space Weapons Ban: Thoughts on a New Treaty}}</ref> Nonetheless, both the Kármán line and the U.S. definition are merely working benchmarks, without any real legal authority over matters of national sovereignty.


The boundary between public airspace and private [[air rights]] is defined by national or local law.
The boundary between public airspace and private [[air rights]] is defined by national or local law.
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In the United States, the 1946 Supreme Court decision ''[[United States v. Causby]]'' overturned the [[common law]] doctrine that private property rights extend indefinitely upwards, instead ruling that they end 300 feet above the highest terrain (including buildings), the lower limit of the "public highway" defined by Congress in the [[Air Commerce Act of 1926]]. The [[Federal Aviation Administration]] regulates the construction and marking of structures taller than 200 feet near airports and 500 feet generally.<ref>{{cite web |url=https://www.faa.gov/newsroom/faa-updates-airspace-obstructions-standards |title=FAA Updates Airspace Obstructions Standards |date=December 8, 2015}}</ref>
In the United States, the 1946 Supreme Court decision ''[[United States v. Causby]]'' overturned the [[common law]] doctrine that private property rights extend indefinitely upwards, instead ruling that they end 300 feet above the highest terrain (including buildings), the lower limit of the "public highway" defined by Congress in the [[Air Commerce Act of 1926]]. The [[Federal Aviation Administration]] regulates the construction and marking of structures taller than 200 feet near airports and 500 feet generally.<ref>{{cite web |url=https://www.faa.gov/newsroom/faa-updates-airspace-obstructions-standards |title=FAA Updates Airspace Obstructions Standards |date=December 8, 2015}}</ref>


== Controlled airspace ==
== Classification ==
{{Main|Controlled airspace}}
Airspace is divided into classes, which dictate what services are provided in different areas. The classes are defined by ICAO, but countries are free to allocate different sections of airspace to different classes as they wish. There are 7 classes, A-G, with progressively less strict restrictions. This classification system was adopted by ICAO on 12 March 1990.<ref>ICAO's airspace classification scheme is defined in ICAO Annex 11: Air Traffic Services, Chapter 2, Section 2.6, available at {{cite web |title=ICAO Annexes - All Documents |url=http://www.icao.int/safety/ism/ICAO%20Annexes/Forms/AllItems.aspx |url-status=dead |archive-url=https://web.archive.org/web/20140407130450/http://www.icao.int/safety/ism/ICAO%20Annexes/Forms/AllItems.aspx |archive-date=2014-04-07 |access-date=2014-04-05}}</ref><ref name=":1">{{Cite web |title=Classification of Airspace {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/classification-airspace |access-date=2025-10-01 |website=skybrary.aero}}</ref>
Controlled airspace is a generic term that covers the different classifications of airspace and defined dimensions within which air traffic control (ATC) service is provided in accordance with the airspace classification. Controlled airspace consists of:<ref name=":0">{{Cite web|title=Pilot's Handbook of Aeronautical Knowledge; FAA-H-8083-25A|last=Federal Aviation Administration|first=U.S. Department of Transportation|publisher=Flight Standard Services|year=2008|url=https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak/media/pilot_handbook.pdf|pages=14–2 to 14–16|url-status=live|archive-url=https://web.archive.org/web/20170430154609/https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak/media/pilot_handbook.pdf|archive-date=30 April 2017}} {{PD-notice}}</ref>
{| class="wikitable"
* Class A
|+
* Class B
!Class
* Class C
!Permitted [[Flight rules (disambiguation)|flight rules]]
* Class D
![[Controlled airspace|Controlled]]
* Class E
!Separation provided
!Services provided
!Radio required
!Requires ATC clearance to enter
|-
|A
|Only [[Instrument flight rules|IFR]]
|{{yes}}
|All aircraft are separated from all others
|Air traffic control service to all flights
|{{yes}}
|{{yes}}
|-
|B
|[[Instrument flight rules|IFR]] and [[Visual flight rules|VFR]]
|{{yes}}
|All aircraft are separated from all others
|Air traffic control service to all flights
|{{yes}}
|{{yes}}
|-
|C
|[[Instrument flight rules|IFR]] and [[Visual flight rules|VFR]]
|{{yes}}
|IFR flights separated from all others. VFR flights receive [[Flight information service|traffic information]] on IFR flights.
|Air traffic control service to all flights
|{{yes}}
|{{yes}}
|-
|D
|[[Instrument flight rules|IFR]] and [[Visual flight rules|VFR]]
|{{yes}}
|IFR flights separated from other IFR flights and receive traffic information on VFR  flights. VFR flights receive traffic information on all other flights.
|Air traffic control service to all flights
|{{yes}}
|{{yes}}
|-
|E
|[[Instrument flight rules|IFR]] and [[Visual flight rules|VFR]]
|{{yes}}
|IFR flights separated from other IFR flights.
|Air traffic control service to IFR flights, traffic information to all flights when practical
|{{yes}}
|{{maybe|Yes for IFR, no for VFR}}
|-
|F
|[[Instrument flight rules|IFR]] and [[Visual flight rules|VFR]]
|{{no}}
|None provided
|Participating IFR flights receive air traffic advisory service. Flight information service to all flights when practical (if available).
|{{no}}
|{{no}}
|-
|G
|[[Instrument flight rules|IFR]] and [[Visual flight rules|VFR]]
|{{no}}
|None provided
|Flight information service to all flights when practical (if available).
|{{no}}
|{{no}}
|-
| colspan="7" style="font-size:80%" | Class F airspace is rarely used and is considered by ICAO to be a temporary measure before it can be replaced by an alternative classification.<ref>{{Cite web |date=2024-12-03 |title=Easy Access Rules for Standardised European Rules of the Air (SERA) - Revision from December 2024 — Available in pdf, online & XML format {{!}} EASA |url=https://www.easa.europa.eu/en/document-library/easy-access-rules/online-publications/easy-access-rules-standardised-european |access-date=2025-10-08 |website=www.easa.europa.eu |language=en}}</ref> For example, the CAA previous classified certain routes where air traffic control only provided an advisory service as Class F, before they were later reclassified as class E in 2014 after an official review.<ref>{{Cite web |date=30 July 2014 |title=REPLACEMENT OF CLASS F AIRSPACE IN UK FIRs |url=https://www.caa.co.uk/media/e1kgslrm/20140715decisionletter_final.pdf |access-date=8 October 2025 |website=CAA}}</ref>
|-
| colspan="7" | Source: Classification of Airspace, SKYbrary Aviation Safety<ref>{{Cite web |title=Classification of Airspace {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/classification-airspace |access-date=2025-09-28 |website=skybrary.aero}}</ref>
|}


=== Class A airspace ===
=== Controlled vs uncontrolled ===
Class A airspace is generally the airspace from 18,000 feet (~3.4&nbsp;miles, 5.5&nbsp;km) [[mean sea level]] (MSL) up to and including [[flight level]] (FL) 600 (~11.4&nbsp;miles, 18.3&nbsp;km), including the airspace overlying the waters within 12 [[nautical mile]]s (NM) (~13.8&nbsp;miles, 22.2&nbsp;km) of the coast of the 48 contiguous states and Alaska. Unless otherwise authorized, all operation in Class A airspace is conducted under instrument flight rules (IFR).<ref name=":0" />


=== Class B airspace ===
==== Controlled airspace ====
Class B airspace is generally airspace from the surface to 10,000 feet MSL surrounding the nation's busiest airports in terms of airport operations or passenger enplanements. The configuration of each Class B airspace area is individually tailored, consists of a surface area and two or more layers (some Class B airspace areas resemble upside-down wedding cakes), and is designed to contain all published instrument procedures once an aircraft enters the airspace. An ATC clearance is required for all aircraft to operate in the area, and all aircraft that are so cleared receive separation services within the airspace.<ref name=":0" />
{{Main|Controlled airspace}}


=== Class C airspace ===
[[File:Airspace classes (United States).svg|thumb|[[United States]] implementation of ICAO airspace classification]]
Class C airspace is generally airspace from the surface to 4,000 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower, are serviced by a radar approach control, and have a certain number of IFR operations or passenger enplanements. Although the configuration of each Class C area is individually tailored, the airspace usually consists of a surface area with a five NM radius, an outer circle with a ten NM radius that extends from 1,200 feet to 4,000 feet above the airport elevation, and an outer area. Each aircraft must establish two-way radio communications with the ATC facility providing air traffic services prior to entering the airspace and thereafter maintain those communications while within the airspace.<ref name=":0" />
[[Controlled airspace]]<ref>{{cite web |url=http://www.faraim.org/aim/aim-4-03-14-131.html |title=AIM Section 2. Controlled Airspace |url-status=dead |archive-url=https://web.archive.org/web/20140607010704/http://www.faraim.org/aim/aim-4-03-14-131.html |archive-date=7 June 2014 }}</ref> exists where it is deemed necessary that [[air traffic control]] has some form of positive executive control over aircraft flying in that airspace (however, air traffic control does not necessarily control traffic operating under [[visual flight rules|visual flight rules (VFR)]]<ref>{{cite web |url=http://www.faraim.org/aim/aim-4-03-14-707.html |title=Pilot/Controller Glossary – VISUAL FLIGHT RULES |url-status=dead |archive-url=https://web.archive.org/web/20141218033959/http://www.faraim.org/aim/aim-4-03-14-707.html |archive-date=18 December 2014}}</ref> within this airspace). Controlled airspace consists of [[Airspace class|classes]] A-E.<ref name=":1" /> Special types of controlled airspace, such as Control Zones (CTR) and Aerodrome Traffic Zones (ATZ) exist to protect aircraft in the vicinity of an airport, typically when arriving or departing.<ref>{{Cite web |title=Aerodrome Traffic Zone (ATZ) {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/aerodrome-traffic-zone-atz |access-date=2025-09-28 |website=skybrary.aero}}</ref><ref>{{Cite web |title=Control Zone (CTR) {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/control-zone-ctr |access-date=2025-10-08 |website=skybrary.aero}}</ref>


=== Class D airspace ===
===== Uncontrolled airspace =====
Class D airspace is generally airspace from the surface to 2,500 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower. The configuration of each Class D airspace area is individually tailored and when instrument procedures are published, the airspace is normally designed to contain the procedures. Arrival extensions for instrument approach procedures (IAPs) may be Class D or Class E airspace. Unless otherwise authorized, each aircraft must establish two-way radio communications with the ATC facility providing air traffic services prior to entering the airspace and thereafter maintain those communications while in the airspace.<ref name=":0" />
 
=== Class E airspace ===
If the airspace is not Class A, B, C, or D, and is controlled airspace, then it is Class E airspace. Class E airspace extends upward from either the surface or a designated altitude to the overlying or adjacent controlled airspace. When designated as a surface area, the airspace is configured to contain all instrument procedures. Also in this class are federal airways, airspace beginning at either 700 or 1,200 feet above ground level (AGL) used to transition to and from the terminal or en route environment, and en route domestic and offshore airspace areas designated below 18,000 feet MSL. Unless designated at a lower altitude, Class E airspace begins at 14,500 MSL over the United States, including that airspace overlying the waters within 12 NM of the coast of the 48 contiguous states and Alaska, up to but not including 18,000 feet MSL, and the airspace above FL 600.<ref name=":0" /> Class E has control services available but VFR pilots are not required to make any contact with ATC unlike other controlled airspace.
 
== Uncontrolled airspace ==
{{Main|Uncontrolled airspace}}
{{Main|Uncontrolled airspace}}


=== Class G airspace ===
[[Uncontrolled airspace]] is airspace in which an [[Air Traffic Control|air traffic control]] (ATC) service is not deemed necessary or cannot be provided for practical reasons. Uncontrolled airspace consists of classes F and G.<ref name=":1" /> A [[flight information service]] may still be provided to participating aircraft in some areas, depending on practicality and availability.<ref>{{Cite web |last=Kelly |first=Brendan |date=2017-05-10 |title=The hidden secrets of UK airspace: Airspace classifications |url=https://nats.aero/blog/2017/05/hidden-secrets-uk-airspace-airspace-classifications/ |access-date=2025-10-01 |website=NATS Blog}}</ref>
Uncontrolled airspace or Class G airspace is the portion of the airspace that has not been designated as Class A, B, C, D, or E. It is therefore designated uncontrolled airspace by the ATC. Class G airspace extends from the surface to the base of the overlying Class E airspace. Although ATC has no authority or responsibility to control air traffic, pilots should remember there are visual flight rules (VFR) minimums which apply to Class G airspace,<ref name=":0" /> and that flight over private property should not be presumed valid.    


== Special use airspace ==
=== Special use airspace ===
{{Main|Special use airspace}}
{{Main|Special use airspace}}
Special use airspace or special area of operation (SAO) is the designation for airspace in which certain activities must be confined, or where limitations may be imposed on aircraft operations that are not part of those activities. Certain special use airspace areas can create limitations on the mixed use of airspace. The special use airspace depicted on instrument charts includes the area name or number, effective altitude, time and weather conditions of operation, the controlling agency, and the chart panel location. On National Aeronautical Charting Group (NACG) en route charts, this information is available on one of the end panels.<ref name=":0" /> Special use airspace usually consists of:
* Prohibited areas
* Restricted areas
* Warning areas
* Military operation areas (MOAs)
* Alert areas
* Controlled firing areas (CFAs)


=== Prohibited areas ===
[[Special use airspace]] (SUA) is airspace designated for operations that may cause limitations on other, uninvolved aircraft and exist to allow countries to separate certain areas of airspace that could be dangerous to flights within them. SUA may be controlled or uncontrolled, and does not have any specific classes associated with it.<ref>{{Cite web |title=Special Use Airspace (SUA) {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/special-use-airspace-sua |access-date=2025-09-28 |website=skybrary.aero}}</ref><ref name=":0">{{Cite web |title=Special Use Airspace |url=https://www.faa.gov/Air_traffic/publications/atpubs/aim_html/chap3_section_4.html |archive-url=https://web.archive.org/web/20250717222805/https://www.faa.gov/Air_traffic/publications/atpubs/aim_html/chap3_section_4.html |archive-date=17 July 2025 |access-date=2025-09-28 |website=www.faa.gov |language=en |url-status=live }}</ref>
{{Main|Prohibited airspace}}
 
Prohibited areas contain airspace of defined dimensions within which the flight of aircraft is prohibited. Such areas are established for security or other reasons associated with the national welfare. Prohibited areas in the United States are published in the ''[[Federal Register]]'' and are depicted on aeronautical charts. The area is charted as a "P" followed by a number (e.g., P-49). Examples of prohibited areas include [[Camp David]] and the [[National Mall]] in Washington, D.C., where the [[White House]] and the [[United States Capitol Complex|Congressional buildings]] are located.<ref name=":0" />
SUA includes:


=== Restricted areas ===
* [[Prohibited airspace]] is areas where flight is prohibited, usually for safety reasons.
{{Main|Restricted airspace}}
* [[Restricted airspace]] is areas where flight is restricted or subject to limitations, and may require permission to enter.
Restricted areas are areas where operations are hazardous to nonparticipating aircraft and contain airspace within which the flight of aircraft, while not wholly prohibited, is subject to restrictions. Activities within these areas must be confined because of their nature, or limitations may be imposed upon aircraft operations that are not a part of those activities, or both. Restricted areas denote the existence of unusual, often invisible, hazards to aircraft (e.g., artillery firing, aerial gunnery, or guided missiles). IFR flights may be authorized to transit the airspace and are routed accordingly. Penetration of restricted areas without authorization from the using or controlling agency may be extremely hazardous to the aircraft and its occupants.<ref name=":0" /> ATC facilities apply the following procedures when aircraft are operating on an IFR clearance (including those cleared by ATC to maintain VFR on top) via a route which lies within joint-use restricted airspace:
# If the restricted area is not active and has been released to the Federal Aviation Administration (FAA), the ATC facility allows the aircraft to operate in the restricted airspace without issuing specific clearance for it to do so.
# If the restricted area is active and has not been released to the FAA, the ATC facility issues a clearance which ensures the aircraft avoids the restricted airspace.
Restricted areas are charted with an "R" followed by a number (e.g., R-4401) and are depicted on the en route chart appropriate for use at the altitude or FL being flown. Restricted area information can be obtained on the back of the chart.


=== Warning areas ===
==== Temporary restrictions ====
Warning areas are similar in nature to restricted areas; however, the United States government does not have sole jurisdiction over the airspace. A warning area is airspace of defined dimensions, extending from 12 NM outward from the coast of the United States, containing activity that may be hazardous to nonparticipating aircraft. The purpose of such areas is to warn nonparticipating pilots of the potential danger. A warning area may be located over domestic or international waters or both. The airspace is designated with a "W" followed by a number (e.g., W-237).<ref>{{Cite PHAK|year=2023|chapter=15|page=4}}</ref>
Airspace may be temporarily restricted for safety. This may be via a [[NOTAM]] or [[Federal Aviation Regulations|temporary flight restriction]] (TFR) for a variety of reasons, such as protecting major sporting events, natural disaster areas, air shows, or VIP movements.<ref name=":8">{{Cite web |title=Flight School 101 - What is a NOTAM? - Aviator Flight Training College |url=http://www.aviator.edu/129/section.aspx/72/post/flight-school-101-what-is-a-notam |archive-url=https://web.archive.org/web/20131203050309/http://www.aviator.edu/129/section.aspx/72/post/flight-school-101-what-is-a-notam |archive-date=2013-12-03 |access-date=2025-10-01 |website=Aviator Flight Training College}}</ref><ref name=":7">{{Cite web |title=Temporary Flight Restrictions |url=https://nbaa.org/aircraft-operations/airspace/alerts/notams-and-tfrs/temporary-flight-restrictions/ |access-date=2025-10-01 |website=NBAA - National Business Aviation Association |language=en-US}}</ref>


=== Military operation areas (MOAs) ===
In the UK, airspace can be temporarily restricted by using a prohibited area, restricted area, or danger area—which designates areas where dangerous activities to flight may be taking place.<ref>{{Cite web |title=Airspace restrictions {{!}} UK Civil Aviation Authority |url=https://www.caa.co.uk/commercial-industry/airspace/event-and-obstacle-notification/airspace-restrictions/ |access-date=2025-10-01 |website=www.caa.co.uk}}</ref><ref>{{Cite web |title=Danger Areas |url=https://infringements.caa.co.uk/tutorial/danger-areas/ |access-date=2025-10-01 |website=CAA Infringement Tutorial |language=en-GB}}</ref>
{{Main|Military operations area}}
MOAs consist of airspace with defined vertical and lateral limits established for the purpose of separating certain military training activities from IFR traffic. Whenever an MOA is being used, nonparticipating IFR traffic may be cleared through an MOA if IFR separation can be provided by ATC. Otherwise, ATC reroutes or restricts nonparticipating IFR traffic. MOAs are depicted on sectional, VFR terminal area, and en route low altitude charts and are not numbered (e.g., "Camden Ridge MOA"). [Figure 14-5] However, the MOA is also further defined on the back of the sectional charts with times of operation, altitudes affected, and the controlling agency.<ref name=":0" />


=== Alert areas ===
== Defense ==
Alert areas are depicted on aeronautical charts with an "A" followed by a number (e.g., A-211) to inform nonparticipating pilots of areas that may contain a high volume of pilot training or an unusual type of aerial activity. Pilots should exercise caution in alert areas. All activity within an alert area shall be conducted in accordance with regulations, without waiver, and pilots of participating aircraft, as well as pilots transiting the area, shall be equally responsible for collision avoidance.<ref name=":0" />
[[File:Passenger aircraft interception emergency training (6).jpg|thumb|A [[Eurofighter Typhoon]] on QRA takes off to conduct training intercepting a passenger aircraft.]]
In countries with an established [[military]], airspace is usually defended to protect national sovereignty. While military flights have to share airspace with civilians, they may use [[Military training route|military training routes]] or other special use airspace to protect civilian flights from dangerous activities.<ref>{{Cite web |title=Defence |url=https://www.nats.aero/services-products/customers/defence/ |access-date=2025-10-01 |website=NATS}}</ref>


=== Controlled firing areas (CFAs) ===
=== NATO Air policing ===
CFAs contain activities, which, if not conducted in a controlled environment, could be hazardous to nonparticipating aircraft. The difference between CFAs and other special use airspace is that activities must be suspended when a spotter aircraft, radar, or ground lookout position indicates an aircraft might be approaching the area. There is no need to chart CFAs since they do not cause a nonparticipating aircraft to change its flightpath.<ref name=":0" />
{{Further|Quick Reaction Alert}}
[[NATO]] conducts air policing missions to protect sovereign European airspace from both enemy military aircraft and civilian aircraft that fail to identify themselves, fail to communicate with air traffic control, or don't follow a flight plan.<ref name="NATO-1">{{cite web |title=NATO Air Policing |url=https://www.ac.nato.int/page5931922/-nato-air-policing}}</ref> They do this by keeping [[fighter aircraft]] in a 24/7 state of [[Quick Reaction Alert|quick reaction alert]], ready to be scrambled at any time.<ref name=":5">{{Cite web |title=Quick reaction alert |url=https://www.raf.mod.uk/what-we-do/overview/quick-reaction-alert/ |access-date=2025-10-02 |website=Royal Air Force |language=en-gb}}</ref>


== Other airspace areas ==
For example, the [[Royal Air Force]] maintains four [[Eurofighter Typhoon|Eurofighter Typhoons]] at 24/7 readiness: two at [[RAF Coningsby]] and two at [[RAF Lossiemouth]].<ref name=":5" /> Some NATO states do not have the capability to conduct QRA over their own territory, such as in the Baltic and Icelandic areas, so other NATO countries provide aircraft to cover instead.<ref>{{cite web |title=Belgium, Netherlands to take turns in policing BENELUX airspace |url=http://www.airn.nato.int/archive/2016/belgium--netherlands-to-take-turns-in-policing-benelux-airspace |url-status=dead |archive-url=https://web.archive.org/web/20170329051848/http://www.airn.nato.int/archive/2016/belgium--netherlands-to-take-turns-in-policing-benelux-airspace |archive-date=2017-03-29 |access-date=2017-04-13}}</ref><ref>{{Cite web |title=Irish ministers under pressure to clarify 'secret deal' for RAF to defend Ireland's airspace in an emergency |url=https://news.sky.com/story/irish-ministers-under-pressure-to-clarify-secret-deal-for-raf-to-defend-irelands-airspace-in-an-emergency-12879084 |access-date=2025-10-02 |website=Sky News |language=en}}</ref> In the United States, the quick reaction alert mission is referred to as Aerospace Control Alert, after having been renamed from Air Sovereignty Alert in 2011.<ref>{{cite magazine |date=3 October 2011 |title=New name, same mission |url=http://www.airforcemag.com/DRArchive/Pages/2011/October%202011/October%2003%202011/NewName,SameMission.aspx |magazine=Air Force Magazine}}</ref> The majority of aerospace control alert missions in the U.S. are carried out by the [[Air National Guard]] using the [[F-15 Eagle]] and [[F-16 Fighting Falcon]] jets.<ref>{{cite web |title=Air sovereignty alert: America's security blanket |url=http://www.hsdl.org/?view&did=697707 |url-status=dead |archive-url=https://web.archive.org/web/20151222143306/http://www.hsdl.org/?view&did=697707 |archive-date=2015-12-22 |access-date=2015-12-18}}</ref><ref>{{cite magazine |date=December 2010 |title=Adm. James Winnefeld, the new NORAD and NORTHCOM boss, closely monitors what's needed to defend North America |url=http://www.airforcemag.com/MagazineArchive/Pages/2010/December%202010/1210sovereignty.aspx |magazine=Air Force Magazine}}</ref>
"Other airspace areas" is a general term referring to the majority of the remaining airspace.<ref name=":0" /> It includes:
* Local airport advisory
* Military training route (MTR)
* Temporary flight restriction (TFR)
* Parachute jump aircraft operations
* Published VFR routes
* Terminal radar service area (TRSA)
* National security area (NSA)


=== Local airport advisory (LAA) ===
=== Air defense identification zones (ADIZ) ===
{{See also|Airspace class (United States)#Airport advisory/information service area}}
{{Main|Air defense identification zone}}
A service provided by facilities, which are located on the landing airport, have a discrete ground-to-air communication frequency or the tower frequency when the tower is closed, automated weather reporting with voice broadcasting, and a continuous ASOS/AWOS data display, other continuous direct reading instruments, or manual observations available to the specialist.<ref name=":0" />


=== Military training routes (MTRs) ===
An [[air defense identification zone]] is a region of airspace where a country identifies, locates, and controls aircraft to protect [[national security]], which, in many cases, can cover airspace outside of the country's sovereign airspace.<ref name="Abeyratne">{{cite journal |last=Abeyratne |first=Ruwantissa |date=2011-09-13 |title=In search of theoretical justification for air defence identification zones |url=http://aviationdevelopment.org/eng/sites/default/files/2011111501_Publication.pdf |url-status=dead |journal=Journal of Transportation Security |publisher=Springer Nature |volume=5 |issue=1 |pages=87–94 |doi=10.1007/s12198-011-0083-2 |issn=1938-7741 |s2cid=153873530 |archive-url=https://web.archive.org/web/20140709162934/http://aviationdevelopment.org/eng/sites/default/files/2011111501_Publication.pdf |archive-date=2014-07-09}}</ref><ref name=":6">{{Cite web |title=Air Defense Identification Zone (ADIZ) {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/air-defense-identification-zone-adiz |access-date=2025-10-01 |website=skybrary.aero}}</ref> A country may impose limitations on aircraft within them, such as requiring a flight plan to be filed.
{{Main|Military training route}}
MTRs are routes used by military aircraft to maintain proficiency in tactical flying. These routes are usually established below 10,000 feet MSL for operations at speeds in excess of 250 knots. Some route segments may be defined at higher altitudes for purposes of route continuity. Routes are identified as IFR (IR), and VFR (VR), followed by a number. [Figure 14-7] MTRs with no segment above 1,500 feet AGL are identified by four number characters (e.g., IR1206, VR1207). MTRs that include one or more segments above 1,500 feet AGL are identified by three number characters (e.g., IR206, VR207). IFR low altitude en route charts depict all IR routes and all VR routes that accommodate operations above 1,500 feet AGL. IR routes are conducted in accordance with IFR regardless of weather conditions. VFR sectional charts depict military training activities such as IR, VR, MOA, restricted area, warning area, and alert area information.<ref name=":0" />


=== Temporary flight restrictions (TFR) ===
In 2013, [[China]] established an [[Air Defense Identification Zone (East China Sea)|ADIZ in the East China Sea]], drawing criticisms from neighbouring countries and the United States, as it overlaps existing zones and imposes requirements on both civilian and military aircraft.<ref name="WSJNov13">{{cite news |last=Page |first=Jeremy |date=Nov 27, 2013 |title=The A to Z on China's Air Defense Identification Zone |url=https://blogs.wsj.com/chinarealtime/2013/11/27/the-a-to-z-on-chinas-air-defense-identification-zone/ |access-date=29 November 2013 |newspaper=[[The Wall Street Journal]]}}</ref><ref name="GlobSec2">{{cite web |title=Air Defense Identification Zone |url=http://www.globalsecurity.org/military/world/china/adiz.htm |access-date=29 November 2013 |publisher=[[GlobalSecurity.org]]}}</ref><ref name="nytimes.com2">Rick Gladstone and Matthew L. Wald (27 November 2013), [https://www.nytimes.com/2013/11/28/world/asia/chinas-move-puts-airspace-in-spotlight.html China's Move Puts Airspace in Spotlight] ''[[The New York Times]]''</ref> Since 2010, China has been planning to establish an ADIZ over the [[South China Sea]], which would raise tensions in the [[Territorial disputes in the South China Sea|existing territorial disputes]]. However, as of 2025, no ADIZ has been created.<ref>{{cite web |date=23 November 2020 |title=Why is There No South China Sea Air Defense Identification Zone? |url=http://www.scspi.org/en/dtfx/why-there-no-south-china-sea-air-defense-identification-zone |website=SCSPI}}</ref><ref>{{cite web |last=Chan |first=Minnie |date=31 May 2020 |title=South China Sea airspace control plan in works by Beijing, PLA source says |url=https://www.scmp.com/news/china/military/article/3086679/beijings-plans-south-china-sea-air-defence-identification-zone |website=[[South China Morning Post]]}}</ref>
{{See also|Federal Aviation Regulations#Temporary flight restrictions}}
A flight data center (FDC) Notice to Airmen ([[NOTAM]]) is issued to designate a TFR. The NOTAM begins with the phrase "FLIGHT RESTRICTIONS" followed by the location of the temporary restriction, effective time period, area defined in statute miles, and altitudes affected. The NOTAM also contains the FAA coordination facility and telephone number, the reason for the restriction, and any other information deemed appropriate. The pilot should check the NOTAMs as part of flight planning.<ref name=":0" />


Some of the purposes for establishing a TFR are:
[[Russia|Russian]] aircraft are frequently tracked by the [[United States]] entering their [[Alaska]] ADIZ,<ref name="Abeyratne2">{{cite journal |last=Abeyratne |first=Ruwantissa |date=2011-09-13 |title=In search of theoretical justification for air defence identification zones |url=http://aviationdevelopment.org/eng/sites/default/files/2011111501_Publication.pdf |url-status=dead |journal=Journal of Transportation Security |publisher=Springer Nature |volume=5 |issue=1 |pages=87–94 |doi=10.1007/s12198-011-0083-2 |issn=1938-7741 |s2cid=153873530 |archive-url=https://web.archive.org/web/20140709162934/http://aviationdevelopment.org/eng/sites/default/files/2011111501_Publication.pdf |archive-date=2014-07-09}}</ref> often triggering QRA responses of American fighters.<ref>{{Cite web |date=25 September 2025 |title=NORAD detects and tracks Russian aircraft operating in the Alaskan Air Defense Identification Zone |url=https://www.norad.mil/Newsroom/Press-Releases/Article/4314460/norad-detects-and-tracks-russian-aircraft-operating-in-the-alaskan-air-defense/ }}</ref><ref>{{Cite web |title=US says Russian military aircraft detected in Alaskan air defense zone |url=https://www.aa.com.tr/en/americas/us-says-russian-military-aircraft-detected-in-alaskan-air-defense-zone/3486259 |access-date=2025-10-01 |website=www.aa.com.tr}}</ref>
* Protect persons and property in the air or on the surface from an existing or imminent hazard.
* Provide a safe environment for the operation of disaster relief aircraft.
* Prevent an unsafe congestion of sightseeing aircraft above an incident or event, which may generate a high degree of public interest.
* Protect declared national disasters for humanitarian reasons in the State of Hawaii.
* Protect the President, Vice President, or other public figures.
* Provide a safe environment for space agency operations.
Since the events of September 11, 2001, the use of TFRs has become much more common. There have been a number of incidents of aircraft incursions into TFRs, which have resulted in pilots undergoing security investigations and certificate suspensions. It is a pilot's responsibility to be aware of TFRs in their proposed area of flight. One way to check is to visit the FAA website([https://web.archive.org/web/20140422101932/http://tfr.faa.gov/]), and verify that there is not a TFR in the area.<ref name=":0" />


=== Parachute jump aircraft operations ===
=== Violations and incidents ===
[[Parachuting|Parachute jump]] aircraft operations are published in the Airport/Facility Directory (A/FD). Sites that are used frequently are depicted on sectional charts.<ref name=":0" />
An airspace violation occurs when an aircraft enters controlled or national airspace without authorisation. Such incidents may be accidental, such as navigation or communication errors, or they may be deliberate, such as military reconnaissance or probing.<ref>{{Cite web |title=Airspace Infringement {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/airspace-infringement#:~:text=Airspace%20infringement%20occurs%20when%20an,not%20contained%20in%20the%20clearance. |access-date=2025-10-01 |website=skybrary.aero}}</ref>


=== Published VFR routes ===
In the [[Cold War]], aircraft such as [[Korean Air Lines Flight 007]] were shot down due to misidentification as enemy military aircraft.<ref>{{Cite web |date=2025-08-27 |title=Korean Air Lines flight 007 {{!}} Missiles, Investigation, & Facts {{!}} Britannica |url=https://www.britannica.com/event/Korean-Air-Lines-flight-007 |access-date=2025-10-01 |website=www.britannica.com |language=en}}</ref> In 2023, a Chinese high altitude [[2023 Chinese balloon incident|balloon entered US airspace]],<ref>{{Cite news |date=2023-02-03 |title=Chinese spy balloon over US is weather device says Beijing |url=https://www.bbc.com/news/world-us-canada-64515033 |access-date=2025-10-01 |work=BBC News |language=en-GB}}</ref> allegedly for intelligence gathering, and was subsequently shot down by an American jet, increasing tensions between the two countries.<ref>{{Cite web |last=Altman |first=Howard |last2=Payne |first2=Stetson |last3=Rogoway |first3=Tyler |date=2023-02-04 |title=F-22 Shoots Down Chinese Spy Balloon Off Carolinas With Missile (Updated) |url=https://www.twz.com/f-22-shoots-down-chinese-spy-balloon-off-carolinas-with-missile |access-date=2025-10-01 |website=The War Zone |language=en-US}}</ref> In August and September 2025, Russia [[Violations of non-combatant airspaces during the Russo-Ukrainian war (2022–present)|repeatedly flew drones and aircraft]] into [[NATO]] airspace, prompting NATO to launch [[Operation Eastern Sentry]] after an [[NATO Article 4|Article 4]] declaration.<ref>{{Cite web |date=2025-09-12 |title=NAVO gaat oostflank versterken na binnendringen Russische drones in Polen |url=https://nos.nl/collectie/13965/artikel/2582171-navo-gaat-oostflank-versterken-na-binnendringen-russische-drones-in-polen |access-date=2025-10-01 |website=nos.nl |language=nl}}</ref>
Published VFR routes are for transitioning around, under, or through some complex airspace. Terms such as VFR flyway, VFR corridor, Class B airspace VFR transition route, and terminal area VFR route have been applied to such routes. These routes are generally found on VFR terminal area planning charts.<ref name=":0" />


=== Terminal radar service areas (TRSAs) ===
== Modernization ==
{{Main|Terminal radar service area}}
TRSAs are areas where participating pilots can receive additional radar services. The purpose of the service is to provide separation between all IFR operations and participating VFR aircraft.<ref name=":0" />


The primary airport(s) within the TRSA become(s) Class D airspace. The remaining portion of the TRSA overlies other controlled airspace, which is normally Class E airspace beginning at 700 or 1,200 feet and established to transition to/from the en route/terminal environment. TRSAs are depicted on VFR sectional charts and terminal area charts with a solid black line and altitudes for each segment. The Class D portion is charted with a blue segmented line. Participation in TRSA services is voluntary; however, pilots operating under VFR are encouraged to contact the radar approach control and take advantage of TRSA service.<ref name=":0" />
=== Performance-based navigation ===
{{Main|Performance-based navigation}}


=== National Security Areas (NSAs) ===
[[Performance-based navigation]] (PBN) is a type of navigation that allows aircraft to use GPS and other satellite navigation instead of only ground-based stations like [[VHF omnidirectional range|VORs]] which improves airspace safety, capacity, and efficiency.<ref>ICAO. ''Doc 9613, Performance-based Navigation (PBN) Manual'', 2008. {{ISBN|978-92-9231-198-8}}</ref><ref>{{Cite web |title=Performance-Based Navigation (PBN) and Area Navigation (RNAV) |url=https://www.faa.gov/air_traffic/publications/atpubs/aim_html/chap1_section_2.html |archive-url=https://web.archive.org/web/20250816160826/https://www.faa.gov/air_traffic/publications/atpubs/aim_html/chap1_section_2.html |archive-date=16 August 2025 |access-date=2025-10-07 |website=www.faa.gov |language=en |url-status=live }}</ref> ICAO and national authorities such as the FAA are gradually redesigning controlled and uncontrolled airspace to support [[Required navigation performance|Required Navigation Performance]] (RNP) and [[Area navigation|Area Navigation]] (RNAV) routes.<ref>{{Cite web |title=Performance based navigation {{!}} Heathrow |url=https://www.heathrow.com/company/local-community/noise/airspace-modernisation/performance-based-navigation |access-date=2025-10-07 |website=Heathrow Airport |language=en-GB}}</ref> This changes allow for more efficient flight paths and reduce the need of maintaining specific physical sensors.<ref>{{Cite web |title=Performance Based Navigation (PBN) {{!}} SKYbrary Aviation Safety |url=https://skybrary.aero/articles/performance-based-navigation-pbn |access-date=2025-10-07 |website=skybrary.aero}}</ref> Projects led by service providers such as [[Hughes Aircraft Company|Hughes Aerospace]] have demonstrated how PBN procedures can be used to optimize traffic flows and reduce noise in congested areas,<ref>{{Cite web |title=Hughes Aerospace PBN Executive Summary |url=https://www.faasafety.gov/files/events/GL/GL15/2024/GL15127506/Hughes_Aerospace_PBN_Executive_Summary.pdf |website=FAA Safety}}</ref> such as the [[Naples Airport (Florida)|Naples Municipal Airport]] in Florida.<ref>{{cite news |last=Layden |first=Laura |date=April 1, 2024 |title=Hughes Aerospace working to improve SWFL airplane traffic |url=https://www.naplesnews.com/story/news/local/2024/04/01/naples-airport-authority-hears-update-on-hughes-aerospace-study/73060107007/ |access-date=October 6, 2025 |newspaper=Naples Daily News}}</ref><ref>{{cite news |last=Layden |first=Laura |date=May 1, 2025 |title=Naples Airport to start testing new flight procedures |url=https://www.naplesnews.com/story/news/local/2025/05/01/naples-airport-to-start-testing-new-flight-procedures/83385627007/ |access-date=October 6, 2025 |newspaper=Naples Daily News}}</ref>
{{Main|National Security Area}}
NSAs consist of airspace of defined vertical and lateral dimensions established at locations where there is a requirement for increased security and safety of ground facilities. Flight in NSAs may be temporarily prohibited by regulation under the provisions of Title 14 of the Code of Federal Regulations (14 CFR) part 99, and prohibitions are disseminated via NOTAM. Pilots are requested to voluntarily avoid flying through these depicted areas.<ref name=":0" />


== See also ==
== See also ==
* [[Index of aviation articles]]
* [[Index of aviation articles]]
* [[Air sovereignty]]
* [[Air sovereignty]]
* [[Airspace class]]
* [[Flyover rights]]
* [[Flyover rights]]
* [[United Nations Convention on the Law of the Sea]]
* [[Space law]]
* [[International Civil Aviation Organization]]
* [[Air traffic control]]


== References ==
== References ==
Line 156: Line 170:
== External links ==
== External links ==
{{Wiktionary}}
{{Wiktionary}}
{{commons category|Airspace}}
{{commons category}}
* [https://www.openflightmaps.org/ open flightmaps]
* [https://www.openflightmaps.org/ open flightmaps]
* [https://web.archive.org/web/20130207075314/http://www.faa.gov/air_traffic/publications/ATpubs/AIM/aim0301.html U.S. airspace, as described in the Aeronautical Information Manual]
* [https://web.archive.org/web/20130207075314/http://www.faa.gov/air_traffic/publications/ATpubs/AIM/aim0301.html U.S. airspace, as described in the Aeronautical Information Manual]
* [https://web.archive.org/web/20190624002456/http://airspacetechnology.com/ AirSpace Technology]
* [http://soaringweb.org/Airspace Worldwide Soaring Turnpoint Exchange: Airspace] (publicly contributed data)
* [http://soaringweb.org/Airspace Worldwide Soaring Turnpoint Exchange: Airspace] (publicly contributed data)
* [http://3dairspace.org.uk Airspace data] in [[Google Earth]] Format (KML)
* [http://3dairspace.org.uk Airspace data] in [[Google Earth]] Format (KML)

Latest revision as of 17:54, 12 January 2026


Not to be confused with Aerospace.


Flight information regions in France

Airspace is the portion of the atmosphere controlled by a country above its territory and territorial waters that fall under the country's sovereignty and regulatory control.

Internationally, allocation and management of airspace is coordinated by the International Civil Aviation Organization (ICAO), which was established through the Chicago Convention in 1947 to unify air traffic. ICAO organizes airspace into Flight Information Regions (FIRs) and provides classification guidelines. National authorities, such as the FAA, CAA, or EASA implement rules and regulations for air traffic control, special-use airspace, and enforcement within their own FIRs.

Airspace can be used for both civilian flight and for defense or military operations, and countries are responsible for protecting their own airspace using measures such as air policing. Legal and technical challenges include the vertical boundary between airspace and outer space and temporary restrictions such as NOTAMs or TFRs.

Legal framework and ownership[edit | edit source]

On 4 April 1947, the International Civil Aviation Organization (ICAO) was established through the Chicago Convention, aimed at unifying and coordinating international air travel.[1] ICAO provides regulations and guidance for countries concerning air navigation, its infrastructure, flight inspection, prevention of unlawful interference, and facilitation of border-crossing procedures for international civil aviation.[2]

Sovereign airspace refers to airspace owned by a country. By law, a country has the right to airspace above its land and waters up to 12 miles from their coast (if present). Beyond 12 miles, airspace is considered international.[3] ICAO divides airspace into Flight Information Regions (FIR) which are sections of airspace dedicated to a specific country. A country is responsible, within its own FIR(s), to provide air traffic control services and regulation for flight.[4][5] This is usually done using a national regulator, such as the FAA, CAA, or EASA, which are able to create their own regulations while still abiding by ICAO guidelines.[6] Some countries may have multiple FIRs, for example, the United States has sole jurisdiction in 24 FIRs.[7] A country may, by international agreement, assume responsibility for providing air traffic control services in parts of international airspace, which then becomes part of their FIR.[8] Certain FIRs are dedicated oceanic sectors which support and control air traffic crossing large oceans such as the North Atlantic, which is made up of 7 FIRs controlled by countries like the UK, Ireland, and Canada.[9]

There is no international agreement on the vertical extent of sovereign airspace,[10] although most countries use the Kármán Line, 100km (62mi), as the legal distinction between airspace and outer space.[11][12][13] However, descending Space Shuttles flew closer than 80 km (50 mi) over other nations, such as Canada, without requesting permission first.[14]

Map of approximately the Northern Hemisphere from Japan & New Guinea (left edge) to the middle of North Atlantic Ocean. The map shows yellow over the continental U.S. and Bahamas, Alaska (and much of the Bering Sea), and a yellow circle around Bermuda. Most of the Northern Pacific is colored blue along with a small section in the middle of the Gulf of Mexico, and the western half of the North Atlantic from roughly the latitude of Maine to the northern edge of the Leeward Islands (or Puerto Rico).
The Federal Aviation Administration (FAA) of the United States provides air traffic control services over U.S. territory and over international waters where it has been delegated such authority by the International Civil Aviation Organization. This map depicts overflight fee regions. The yellow regions are where the U.S. provides enroute ATC services (mostly over land territory). The blue regions are where the U.S. provides oceanic ATC services over international waters.

Private air rights[edit | edit source]

The boundary between public airspace and private air rights is defined by national or local law.

In the United States, the 1946 Supreme Court decision United States v. Causby overturned the common law doctrine that private property rights extend indefinitely upwards, instead ruling that they end 300 feet above the highest terrain (including buildings), the lower limit of the "public highway" defined by Congress in the Air Commerce Act of 1926. The Federal Aviation Administration regulates the construction and marking of structures taller than 200 feet near airports and 500 feet generally.[15]

Classification[edit | edit source]

Airspace is divided into classes, which dictate what services are provided in different areas. The classes are defined by ICAO, but countries are free to allocate different sections of airspace to different classes as they wish. There are 7 classes, A-G, with progressively less strict restrictions. This classification system was adopted by ICAO on 12 March 1990.[16][17]

Class Permitted flight rules Controlled Separation provided Services provided Radio required Requires ATC clearance to enter
A Only IFR Yes All aircraft are separated from all others Air traffic control service to all flights Yes Yes
B IFR and VFR Yes All aircraft are separated from all others Air traffic control service to all flights Yes Yes
C IFR and VFR Yes IFR flights separated from all others. VFR flights receive traffic information on IFR flights. Air traffic control service to all flights Yes Yes
D IFR and VFR Yes IFR flights separated from other IFR flights and receive traffic information on VFR flights. VFR flights receive traffic information on all other flights. Air traffic control service to all flights Yes Yes
E IFR and VFR Yes IFR flights separated from other IFR flights. Air traffic control service to IFR flights, traffic information to all flights when practical Yes Yes for IFR, no for VFR
F IFR and VFR No None provided Participating IFR flights receive air traffic advisory service. Flight information service to all flights when practical (if available). No No
G IFR and VFR No None provided Flight information service to all flights when practical (if available). No No
Class F airspace is rarely used and is considered by ICAO to be a temporary measure before it can be replaced by an alternative classification.[18] For example, the CAA previous classified certain routes where air traffic control only provided an advisory service as Class F, before they were later reclassified as class E in 2014 after an official review.[19]
Source: Classification of Airspace, SKYbrary Aviation Safety[20]

Controlled vs uncontrolled[edit | edit source]

Controlled airspace[edit | edit source]

Main article: Controlled airspace
United States implementation of ICAO airspace classification

Controlled airspace[21] exists where it is deemed necessary that air traffic control has some form of positive executive control over aircraft flying in that airspace (however, air traffic control does not necessarily control traffic operating under visual flight rules (VFR)[22] within this airspace). Controlled airspace consists of classes A-E.[17] Special types of controlled airspace, such as Control Zones (CTR) and Aerodrome Traffic Zones (ATZ) exist to protect aircraft in the vicinity of an airport, typically when arriving or departing.[23][24]

Uncontrolled airspace[edit | edit source]
Main article: Uncontrolled airspace

Uncontrolled airspace is airspace in which an air traffic control (ATC) service is not deemed necessary or cannot be provided for practical reasons. Uncontrolled airspace consists of classes F and G.[17] A flight information service may still be provided to participating aircraft in some areas, depending on practicality and availability.[25]

Special use airspace[edit | edit source]

Main article: Special use airspace

Special use airspace (SUA) is airspace designated for operations that may cause limitations on other, uninvolved aircraft and exist to allow countries to separate certain areas of airspace that could be dangerous to flights within them. SUA may be controlled or uncontrolled, and does not have any specific classes associated with it.[26][27]

SUA includes:

  • Prohibited airspace is areas where flight is prohibited, usually for safety reasons.
  • Restricted airspace is areas where flight is restricted or subject to limitations, and may require permission to enter.

Temporary restrictions[edit | edit source]

Airspace may be temporarily restricted for safety. This may be via a NOTAM or temporary flight restriction (TFR) for a variety of reasons, such as protecting major sporting events, natural disaster areas, air shows, or VIP movements.[28][29]

In the UK, airspace can be temporarily restricted by using a prohibited area, restricted area, or danger area—which designates areas where dangerous activities to flight may be taking place.[30][31]

Defense[edit | edit source]

A Eurofighter Typhoon on QRA takes off to conduct training intercepting a passenger aircraft.

In countries with an established military, airspace is usually defended to protect national sovereignty. While military flights have to share airspace with civilians, they may use military training routes or other special use airspace to protect civilian flights from dangerous activities.[32]

NATO Air policing[edit | edit source]

Further information: Quick Reaction Alert

NATO conducts air policing missions to protect sovereign European airspace from both enemy military aircraft and civilian aircraft that fail to identify themselves, fail to communicate with air traffic control, or don't follow a flight plan.[33] They do this by keeping fighter aircraft in a 24/7 state of quick reaction alert, ready to be scrambled at any time.[34]

For example, the Royal Air Force maintains four Eurofighter Typhoons at 24/7 readiness: two at RAF Coningsby and two at RAF Lossiemouth.[34] Some NATO states do not have the capability to conduct QRA over their own territory, such as in the Baltic and Icelandic areas, so other NATO countries provide aircraft to cover instead.[35][36] In the United States, the quick reaction alert mission is referred to as Aerospace Control Alert, after having been renamed from Air Sovereignty Alert in 2011.[37] The majority of aerospace control alert missions in the U.S. are carried out by the Air National Guard using the F-15 Eagle and F-16 Fighting Falcon jets.[38][39]

Air defense identification zones (ADIZ)[edit | edit source]

Main article: Air defense identification zone

An air defense identification zone is a region of airspace where a country identifies, locates, and controls aircraft to protect national security, which, in many cases, can cover airspace outside of the country's sovereign airspace.[40][41] A country may impose limitations on aircraft within them, such as requiring a flight plan to be filed.

In 2013, China established an ADIZ in the East China Sea, drawing criticisms from neighbouring countries and the United States, as it overlaps existing zones and imposes requirements on both civilian and military aircraft.[42][43][44] Since 2010, China has been planning to establish an ADIZ over the South China Sea, which would raise tensions in the existing territorial disputes. However, as of 2025, no ADIZ has been created.[45][46]

Russian aircraft are frequently tracked by the United States entering their Alaska ADIZ,[47] often triggering QRA responses of American fighters.[48][49]

Violations and incidents[edit | edit source]

An airspace violation occurs when an aircraft enters controlled or national airspace without authorisation. Such incidents may be accidental, such as navigation or communication errors, or they may be deliberate, such as military reconnaissance or probing.[50]

In the Cold War, aircraft such as Korean Air Lines Flight 007 were shot down due to misidentification as enemy military aircraft.[51] In 2023, a Chinese high altitude balloon entered US airspace,[52] allegedly for intelligence gathering, and was subsequently shot down by an American jet, increasing tensions between the two countries.[53] In August and September 2025, Russia repeatedly flew drones and aircraft into NATO airspace, prompting NATO to launch Operation Eastern Sentry after an Article 4 declaration.[54]

Modernization[edit | edit source]

Performance-based navigation[edit | edit source]

Main article: Performance-based navigation

Performance-based navigation (PBN) is a type of navigation that allows aircraft to use GPS and other satellite navigation instead of only ground-based stations like VORs which improves airspace safety, capacity, and efficiency.[55][56] ICAO and national authorities such as the FAA are gradually redesigning controlled and uncontrolled airspace to support Required Navigation Performance (RNP) and Area Navigation (RNAV) routes.[57] This changes allow for more efficient flight paths and reduce the need of maintaining specific physical sensors.[58] Projects led by service providers such as Hughes Aerospace have demonstrated how PBN procedures can be used to optimize traffic flows and reduce noise in congested areas,[59] such as the Naples Municipal Airport in Florida.[60][61]

See also[edit | edit source]

References[edit | edit source]

  1. ↑ "Convention on International Civil Aviation". International Civil Aviation Organization. Doc 7300. Retrieved 5 June 2021.
  2. ↑ Wragg, David W. (1973). A Dictionary of Aviation (first ed.). Osprey. p. 165. ISBN 9780850451634.
  3. ↑ "Understanding airspace | UK Civil Aviation Authority". www.caa.co.uk. Retrieved 1 October 2025.
  4. ↑ "Air Traffic Control Service | SKYbrary Aviation Safety". skybrary.aero. Retrieved 1 October 2025.
  5. ↑ "Flight Information Region (FIR) | SKYbrary Aviation Safety". skybrary.aero. Retrieved 1 October 2025.
  6. ↑ "Convention on International Civil Aviation" (PDF). UN. p. 6. Retrieved 1 October 2025.
  7. ↑ "Current FIR Status". ICAO. 5 November 2013. Retrieved 12 August 2025.
  8. ↑ "The Legal Principles Governing the Control of National Airspace and Flight Information Regions and their Application to the Eastern Mediterranean" (PDF). Archived (PDF) from the original on 21 June 2019. Retrieved 21 June 2019.
  9. ↑ "North Atlantic Operations - Airspace". skybrary.aero. Retrieved 1 November 2025.
  10. ↑ Harris, Alexandra; Harris, Ray (2006). "The need for air space and outer space demarcation". Space Policy. 22 (1): 3–7. Bibcode:2006SpPol..22....3H. doi:10.1016/j.spacepol.2005.11.004.
  11. ↑ Byers, Michael; Boley, Aaron (2022). Who Owns Outer Space?: International Law, Astrophysics, and the Sustainable Development of Space. Cambridge University Press. p. 13. ISBN 9781108597135.
  12. ↑ "Who owns outer space?". BBC News. 24 September 2015. Retrieved 1 October 2025.
  13. ↑ Sanz Fernández de Córdoba, Dr. S. (24 June 2004). "The 100 km Boundary for Astronautics". Fédération aéronautique internationale. Retrieved 28 December 2020.
  14. ↑ White, Robert E. "'Space Weapons Ban: Thoughts on a New Treaty". Archived from the original on 15 May 2008. Retrieved 27 July 2007.
  15. ↑ "FAA Updates Airspace Obstructions Standards". 8 December 2015.
  16. ↑ ICAO's airspace classification scheme is defined in ICAO Annex 11: Air Traffic Services, Chapter 2, Section 2.6, available at "ICAO Annexes - All Documents". Archived from the original on 7 April 2014. Retrieved 5 April 2014.
  17. ↑ 17.0 17.1 17.2 "Classification of Airspace | SKYbrary Aviation Safety". skybrary.aero. Retrieved 1 October 2025.
  18. ↑ "Easy Access Rules for Standardised European Rules of the Air (SERA) - Revision from December 2024 — Available in pdf, online & XML format | EASA". www.easa.europa.eu. 3 December 2024. Retrieved 8 October 2025.
  19. ↑ "REPLACEMENT OF CLASS F AIRSPACE IN UK FIRs" (PDF). CAA. 30 July 2014. Retrieved 8 October 2025.
  20. ↑ "Classification of Airspace | SKYbrary Aviation Safety". skybrary.aero. Retrieved 28 September 2025.
  21. ↑ "AIM Section 2. Controlled Airspace". Archived from the original on 7 June 2014.
  22. ↑ "Pilot/Controller Glossary – VISUAL FLIGHT RULES". Archived from the original on 18 December 2014.
  23. ↑ "Aerodrome Traffic Zone (ATZ) | SKYbrary Aviation Safety". skybrary.aero. Retrieved 28 September 2025.
  24. ↑ "Control Zone (CTR) | SKYbrary Aviation Safety". skybrary.aero. Retrieved 8 October 2025.
  25. ↑ Kelly, Brendan (10 May 2017). "The hidden secrets of UK airspace: Airspace classifications". NATS Blog. Retrieved 1 October 2025.
  26. ↑ "Special Use Airspace (SUA) | SKYbrary Aviation Safety". skybrary.aero. Retrieved 28 September 2025.
  27. ↑ "Special Use Airspace". www.faa.gov. Archived from the original on 17 July 2025. Retrieved 28 September 2025.
  28. ↑ "Flight School 101 - What is a NOTAM? - Aviator Flight Training College". Aviator Flight Training College. Archived from the original on 3 December 2013. Retrieved 1 October 2025.
  29. ↑ "Temporary Flight Restrictions". NBAA - National Business Aviation Association. Retrieved 1 October 2025.
  30. ↑ "Airspace restrictions | UK Civil Aviation Authority". www.caa.co.uk. Retrieved 1 October 2025.
  31. ↑ "Danger Areas". CAA Infringement Tutorial. Retrieved 1 October 2025.
  32. ↑ "Defence". NATS. Retrieved 1 October 2025.
  33. ↑ "NATO Air Policing".
  34. ↑ 34.0 34.1 "Quick reaction alert". Royal Air Force. Retrieved 2 October 2025.
  35. ↑ "Belgium, Netherlands to take turns in policing BENELUX airspace". Archived from the original on 29 March 2017. Retrieved 13 April 2017.
  36. ↑ "Irish ministers under pressure to clarify 'secret deal' for RAF to defend Ireland's airspace in an emergency". Sky News. Retrieved 2 October 2025.
  37. ↑ "New name, same mission". Air Force Magazine. 3 October 2011.
  38. ↑ "Air sovereignty alert: America's security blanket". Archived from the original on 22 December 2015. Retrieved 18 December 2015.
  39. ↑ "Adm. James Winnefeld, the new NORAD and NORTHCOM boss, closely monitors what's needed to defend North America". Air Force Magazine. December 2010.
  40. ↑ Abeyratne, Ruwantissa (13 September 2011). "In search of theoretical justification for air defence identification zones" (PDF). Journal of Transportation Security. 5 (1). Springer Nature: 87–94. doi:10.1007/s12198-011-0083-2. ISSN 1938-7741. S2CID 153873530. Archived from the original (PDF) on 9 July 2014.
  41. ↑ "Air Defense Identification Zone (ADIZ) | SKYbrary Aviation Safety". skybrary.aero. Retrieved 1 October 2025.
  42. ↑ Page, Jeremy (27 November 2013). "The A to Z on China's Air Defense Identification Zone". The Wall Street Journal. Retrieved 29 November 2013.
  43. ↑ "Air Defense Identification Zone". GlobalSecurity.org. Retrieved 29 November 2013.
  44. ↑ Rick Gladstone and Matthew L. Wald (27 November 2013), China's Move Puts Airspace in Spotlight The New York Times
  45. ↑ "Why is There No South China Sea Air Defense Identification Zone?". SCSPI. 23 November 2020.
  46. ↑ Chan, Minnie (31 May 2020). "South China Sea airspace control plan in works by Beijing, PLA source says". South China Morning Post.
  47. ↑ Abeyratne, Ruwantissa (13 September 2011). "In search of theoretical justification for air defence identification zones" (PDF). Journal of Transportation Security. 5 (1). Springer Nature: 87–94. doi:10.1007/s12198-011-0083-2. ISSN 1938-7741. S2CID 153873530. Archived from the original (PDF) on 9 July 2014.
  48. ↑ "NORAD detects and tracks Russian aircraft operating in the Alaskan Air Defense Identification Zone". 25 September 2025.
  49. ↑ "US says Russian military aircraft detected in Alaskan air defense zone". www.aa.com.tr. Retrieved 1 October 2025.
  50. ↑ "Airspace Infringement | SKYbrary Aviation Safety". skybrary.aero. Retrieved 1 October 2025.
  51. ↑ "Korean Air Lines flight 007 | Missiles, Investigation, & Facts | Britannica". www.britannica.com. 27 August 2025. Retrieved 1 October 2025.
  52. ↑ "Chinese spy balloon over US is weather device says Beijing". BBC News. 3 February 2023. Retrieved 1 October 2025.
  53. ↑ Altman, Howard; Payne, Stetson; Rogoway, Tyler (4 February 2023). "F-22 Shoots Down Chinese Spy Balloon Off Carolinas With Missile (Updated)". The War Zone. Retrieved 1 October 2025.
  54. ↑ "NAVO gaat oostflank versterken na binnendringen Russische drones in Polen". nos.nl (in Nederlands). 12 September 2025. Retrieved 1 October 2025.
  55. ↑ ICAO. Doc 9613, Performance-based Navigation (PBN) Manual, 2008. ISBN 978-92-9231-198-8
  56. ↑ "Performance-Based Navigation (PBN) and Area Navigation (RNAV)". www.faa.gov. Archived from the original on 16 August 2025. Retrieved 7 October 2025.
  57. ↑ "Performance based navigation | Heathrow". Heathrow Airport. Retrieved 7 October 2025.
  58. ↑ "Performance Based Navigation (PBN) | SKYbrary Aviation Safety". skybrary.aero. Retrieved 7 October 2025.
  59. ↑ "Hughes Aerospace PBN Executive Summary" (PDF). FAA Safety.
  60. ↑ Layden, Laura (1 April 2024). "Hughes Aerospace working to improve SWFL airplane traffic". Naples Daily News. Retrieved 6 October 2025.
  61. ↑ Layden, Laura (1 May 2025). "Naples Airport to start testing new flight procedures". Naples Daily News. Retrieved 6 October 2025.

External links[edit | edit source]

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