registry. All civil aircraft registered in countries belonging to the International Civil Aviation Organization are required to be marked with symbols and designations of nationality. 20 State aircraft, including military aircraft, are also marked to indicate their nationality. The attribution of nationality to aircraft reflects the legal relationships between the state whose "flag" the aircraft carries and that craft. Thus, the flag state is responsible for the international good conduct of the aircraft when it operates beyond its national boundaries. The flag state exercises jurisdiction over the craft of the flag state and asserts on behalf of the aircraft the privileges and immunities to which it is entitled when in international airspace or in the airspace of other states. The flag state also has jurisdiction over the personnel who operate the craft. 21

c. Historic Problem in Defining "Military Aircraft." The principal international conventions relating to aircraft distinguish between "state" aircraft and "civil" aircraft. Article 3(b) of the Chicago Convention of 1944 defines "state" aircraft as "aircraft used in military, customs and police services." The earliest efforts to characterize aircraft as "military" were based upon the character of the commander of the craft. If he was a uniformed member of the military services and had on board a certificate of military character, the aircraft would be considered military. In the wake of World War I, some effort was made to distinguish between civil and military aircraft on the basis of design. Later commentators pointed out the impossibility in distinguishing aircraft on the basis of design, and therefore use was the principal basis upon which aircraft were distinguished. 22

d. Present Status. At the present time, no single aspect of ownership, use or control is recognized as decisive for distinguishing military from other types of aircraft. A comparison to the definition of warships in Article 8(2) of the Convention on the High Seas may be drawn:

"... the term 'warship' means a ship belonging to the naval forces of a State

and bearing the external marks distinguishing warships of its nationality, under the command of an officer duly commissioned by the government and whose name appears on the Navy List, and manned by a crew who are under regular naval discipline."

The operation of aircraft not owned by a government, but used for government purposes, including the military services, has raised a variety of questions concerning taxes, landing fees, and other issues dependent upon the legal status of the aircraft. 23

Other forms of state aircraft, such as aircraft used in customs or police services, are not regarded as military aircraft. Accordingly, their markings should differ from those applied to military aircraft. In armed conflict they are assimilated to civil aircraft for purposes of determining belligerency rights and vulnerability to attack. 24

e. Medical Aircraft. Military aircraft engaged exclusively in specified medical functions are subject to a separate legal regime under the 1949 Geneva Conventions. 25

2-5. Access by Military Aircraft to Airspace During Peacetime:

a. General Principles. Military aircraft of any state are free to operate in international airspace without interference from any other state. However, military aircraft are not entitled to enter the national airspace of any other state without the consent of that state. Military aircraft entering the national airspace or landing on the territory of another sovereign with the latter's consent do so subject to the terms and conditions of that consent. 26 As a general proposition of international law, military aircraft present in the territory of a foreign country with its permission are exempt from search, seizure, or inspection by that country's authorities. 27 However, the crews of military aircraft may be subject to the jurisdictional provisions of applicable status of forces agreements. Unless inconsistent with an applicable status of forces or other international agreement, the United States generally asserts immunity for its military aircraft and crews entering

the national airspace or landing on the territory of a foreign country with its consent.

b. Nonapplicability of Chicago Convention to Military Aircraft and Other State Aircraft. Article 3 of the 1944 Chicago Convention on International Civil Aviation provides:

(a) This Convention shall be applicable only to civil aircraft, and shall not be applicable to state aircraft.

(b) Aircraft used in military, customs and police services shall be deemed to be state aircraft.

(c) No state aircraft of a contracting State shall fly over the territory of another State or land thereon without authorization by special agreement or otherwise, and in accordance with the terms thereof.

(d) The contracting States undertake, when issuing regulations for their state aircraft, that they will have due regard for the safety of navigation of civil aircraft.

Thus, other than iterating the general principle of international law that state aircraft require the consent of another sovereign for entry into its airspace or landing on its territory, and establishing a duty for parties to the Convention to regulate their state aircraft in such a manner that they have "due regard for the safety of navigation of civil aircraft," the provisions of the Chicago Convention, as well as the standards, practices and procedures of the International Civil Aviation Organization (ICAO) established thereunder, do not apply to military aircraft. The United States Government has issued a detailed statement of its position on the effect of Article 3 on the relationship of the Chicago Convention to military and other state aircraft. 29

c. Intrusions Into National Airspace Based on Self-Defense:

In the Cuban situation in 1962, the aerial surveillance of the island was also justified on the basis of the United States' inherent rights of self-defense, recognized in customary international law, the United Nations Charter, and participation in the collective

self-defense efforts of the Organization of American States (OAS).

Self-defense is properly invoked only when a threat is apparent and immediate. and when the measures are proportional in means and degree to the threat perceived. 30 A general concern about surprise attack without evidence of immediacy, does not render transit through the national airspace for purpose of photographing the ground a proportional act. 31

d. Intrusions Into National Airspace Based on Mistake or Duress. No settled international rule permits intrusions of military aircraft into national airspace on grounds of mistake, duress, distress or other force majeure. An intruding military aircraft must obey orders to leave or land and, failing a proper and prompt response, can be attacked and destroyed, even in hot pursuit in international airspace. Hot pursuit refers to immediate and continuous pursuit when engaged aircraft have not lost contact with each other for a period of time and not involving contact in the airspace of another sovereign state. 32

The use of force against an intruding military aircraft, however, is subject to the general rule of international law that the employment of measures of force to protect territorial sovereignty is subject to the duty to "take into consideration the elementary obligations of humanity, and not to use a degree of force in excess of what is commensurate with the reality and the gravity of the threat...

33

e. Peripheral Surveillance. While a state has broad rights to prevent any physical intrusion of its national airspace by military aircraft of another state, the United States has maintained the view that a state has no right to prevent the use of international airspace for purposes of surveillance or observation of its airspace or territory. It is common practice for military aircraft to fly in the international airspace adjacent to the national airspace of other states for purposes of photographing and otherwise observing activities within the national airspace or territory.

1

1

12-6. Access to Airspace by Military Aircraft During Hostilities:

a. General Principles of Access. The general principles applicable to military aircraft in time of peace also apply during armed conflict. The rule as between parties to an armed conflict is stated in paragraph 4-2a. Consideration of the rights and obligations of neutrals is also particularly relevant during armed conflict. Each neutral state can, in self-defense, attack hostile aircraft and continue to prevent intrusion into its own airspace.

b. Combat Zones. Parties to a conflict are not prohibited from establishing areas of immediate air operations within which they pursue combat activities. Notice of the existence of such areas must be given. Such zones may exist over the territories and territorial waters of all states involved in given hostilities. All aircraft entering such zones, including the aircraft of neutral states, are subject to damages from military hostilities. 34 However, belligerents may not deny access to international airspace by neutrals and must permit transit through international airspace by neutral aircraft even if bound for enemy territory.

c. Neutral Airspace. The territory and, hence, the airspace above the territory of neutrals is inviolable. 35 This includes recognized territorial waters. Therefore, belligerent aircraft may not enter the airspace of a neutral, even in hot pursuit (unless the neutral airspace is a sanctuary for the adversary). Offenders may be repulsed with force by the neutral, and may be liable for damages caused the neutral as a result of the intrusion. The right of territorial integrity is coupled with a duty to avoid violations of that neutrality by parties to a conflict including the expansion of the conflict into their territory or the use of their territory as a base of operations. Should the neutral be unable or fail to prevent recurring violations by one belligerent, opposing belligerents are entitled to take appropriate measures in self defense. This may involve entry into the neutral territory (or airspace) to attack the adversary. The decision to do so is a political decision to be made at an appropri

ately high political level. Belligerent aircraft that are downed by a neutral, or which in distress or similar circumstances land on the territory of a neutral, are to be detained by the neutral until the cessation of hostilities and then returned to the belligerent from which they originated. Military personnel in such aircraft are to be similarly detained during the conflict and returned at the end of hostilities. 36

d. Military Aircraft Have Belligerent Status. Aircraft are considered entities of combat in the same manner as ships. Thus, the aircraft, as such, has the status of a combatant aircraft and must, accordingly, be properly identified to enable other combatants and neutral forces to recognize its status. Only military aircraft may exercise such rights of belligerents as attacking and destroying military objectives or transporting troops in the adversary's national airspace or behind its lines.

Although civil aircraft may be used for support missions, such as transporting troops or supplies in international airspace or over friendly national airspace, such aircraft are not entitled to engage in direct combat operations unless they are designated as state aircraft. Civil aircraft must not be marked with the distinctive markings of military aircraft, nor may they be armed. Combat in the airspace and attacks on various categories of aircraft are discussed in chapter 4.

e. Medical Aircraft. 37 To enjoy effective immunity, medical aircraft must be clearly marked with the red cross or other comparable, internationally recognized symbols. To enjoy specific treaty immunity they must follow the flight paths, elevation and times specifically agreed upon by the belligerents. Medical aircraft cannot retain status as protected medical aircraft during any flight in which they engage in any activity other than the transportation of patients and medical personnel or medical equipment and supplies. Use of the red cross during such a mission would be perfidious and unlawful. The medical and operational personnel of medical aircraft are also entitled to special protections under the Geneva Conventions.

'The International Air Navigation Conference of Paris was convened in 1910 to consider French objections to German balloons carrying German military personnel crossing into French airspace. The rule of territoriality of airspace there asserted was then incorporated into the first multilateral agreement on the subject, the Paris Convention of 1919, and is the very first article of the present multinational Convention applicable to the regulation of civil aviation, the Chicago Convention of 1944. See Cooper, "The International Air Navigation Conference, Paris 1910," 19 J. Air L. & Com. 127, 128-9 (1952); Convention Relating to the Regulation of Aerial Navigation (Paris 1919), Article 1, reprinted in English in Cooper, The Right to Fly 291 (1947); Article 1, Convention on International Civil Aviation (Chicago 1944), 61 Stat 1180; TIAS 1591; 3 Bevans 944 15 UNTS 295; AFP 110-20, at 5-2 (1947) [hereafter Chicago Convention].

2 The existence of atmosphere is relevant, since the Chicago Convention defines "aircraft" as a “machine that can derive support in the atmosphere from the reactions of the air." Annex 7. This includes pilotless craft. Article 8. The altitude at which the component atoms of the air begin to dissociate, the Von Karman line, is approximately 50 miles above the earth's surface. The altitude above which aerodynamic forces on spacecraft for orbit or reentry can usually be disregarded is about 62 miles. United States domestic law defines aircraft as a "contrivance . . . used or designed for navigation of or flight in air." 49 U.S.C. § 1301(5) (1970). For present purposes the terms "atmosphere" and "air" can be considered synonymous.

3 See, e.g., Federal Aviation Act of 1958, § 103(c), 49 U.S.C. § 1303(c) (1970).

4 Article 14, 1958 Convention on the Territorial Sea and the Contiguous Zone, 15 UST 1606; TIAS 5639; 516 UNTS 205; AFP 110-20, at 7-2 (1964). As to passage for space entry, see Christol, infra note 14. The Space Treaty does recognize a right of innocent passage in case of distress by its provision for emergency landings and the commitment of signatories both to assist astronants in such circumstances and to return space vehicles so landing to their state of registry. Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies, Art V, 18 UST 2411; TIAS 6347; 610 UNTS 205; AFP 110-20, at 6–2 (1967) [hereafter Space Treaty]; Agreement on the Rescue of Astronauts, the Return of Astronauts, and the Return of Objects Launched Into Outer Space, Arts 1 and 2, 19 UST 7570; TIAS 6599; 672 UNTS 119; AFP 110-20, at 6-6 (1968).

5 Convention on the High Seas of April 29, 1958, 13 UST 2312; TIAS 5200; 450 UNTS 82; AFP 11020, at 7-10 (1962).

6 The United States does not recognize claims to territorial seas in excess of 3 miles in breadth. As a condition for agreement in a new Law of the Sea Convention that the territorial sea may extend up to 12 miles, the United States insists that the right of unimpeded transit through and over international straits be maintained. See also United States v. California, 332 U.S. 19, 32-34 (1947).

7 Various claims to territorial seas in excess of three miles have been advanced and protested, some up to 200 miles. The United Nations has studied the issue extensively, and several sessions of a Diplomatic Conference have met and may soon conclude agreement on the issue of the proper breadth of the territorial sea. 4 Whiteman, Digest of International Law 19-35 (1965) [hereafter cited as Whiteman]; Department of State, International Boundary Study. Series A, Limits in the Seas (March 1, 1973).

• There are probably no remaining uninhabited and unclaimed land areas in the world where airspace would be subject to the same freedom of overflight as over the high seas. Pursuant to the Antarctic Treaty, however, each party is assured the right to fly over Antarctica for aerial observation. On the other hand, all measures of a military nature are prohibited, although military personnel and equipment may be used for "peaceful purposes." See Article VII, Antarctic Treaty, 12 UST 794; TIAS 4780; 402 UNTS 71; AFP 110-20, at 11-25 (1961). 9 15 UST 1606; TIAS 5639; 516 UNTS 205; AFP 110-20, at 7-2 (1964).

10 See discussion and authorities cited in notes 6 and 7 supra.

11 14 CFR § 99.1(a)-99.49 (1976). Although identification is not required of state aircraft, including military aircraft, the USAF requires its aircraft, and encourages foreign military aircraft, to adhere to the identification procedures of the US ADIZS and has recognized the propriety of the establishment of ADIZS by other governments with which USAF aircraft may comply if the identification procedures are comparable to the standards applied by the United States. See paragraph 5, AFR 60-22 (17 April 70).

12 Article 11 of the Chicago Convention expressly recognizes the right of a state to establish laws and regulations relating to the admission to or departure from its territory of aircraft engaged in international air navigation.

13 From time to time, and for temporary purposes and times, states have declared certain areas of international airspace as "warning zones." Exam

ples include where practice maneuvers are under way, or where, prior to the Test Ban Treaty, nuclear weapons were tested. Appropriate international "Notices to Airmen" (NOTAM's) must be issued, which, under USAF regulation applicable to activities in international airspace over the high seas, must keep the airspace and time involved to a minimum. Paragraph 7, AFR 60-28 (23 Oct 62). When a state identifies a hazardous area above the high seas, however, it does not purport to have * authority to prohibit aircraft of other states from flying through that airspace or to punish the owners or operators of such aircraft.

14 Space Treaty, supra note 4; Christol, “ 'Innocent Passage' in the International law of Outer Space," 7 AF JAG L. Rev., No. 5, 22 (1965); Fawcett, International Law and the Uses of Outer Space 22 (1968); and authorities in 2 Whiteman 300 (1963).

15 DeSaussure and Reed, "Self Defense-A Right in Outer Space," 7 AF JAG L. Rev. No. 5, 38 (1965).

116 A right of intrusion in the exercise of self-defense may also be recognized. See Fedele, "Overflight By Military Aircraft in Time of Peace," 9 AF JAG L. Rev. No. 5, 8, 23 (1967).

17 See, e.g., bilateral air rights agreement with Spain in Procedural Annex VII to the Agreement in Implementation of Chapter VIII of the Agreement of Friendship and Cooperation between the United States and Spain, 21 UST 2259; TIAS 6977; AFP 10-20, at 4-48, 4-64 (1970); with the Netherlands, 13 UST 488; TIAS 5013 (1962); with Japan in Article V, of the Agreement Under Article VI of * the Treaty of Mutual Cooperation and Security Between the United States and Japan, 11 UST 1652; TIAS 4510; 373 UNTS 248; AFP 110-20, at 4-19, 4-20 (1960).

18 For a comprehensive review, see Reed, "The Outer Space Treaty; Freedoms-Prohibitions-Duties," 9 AF JAG L. Rev. No. 5, 26 (1967).

19 The generalized obligations of the Space Treaty have been amplified by the specific Assistance Treaty, supra note 4, and the Convention on the International Liability for Damage Caused by Space : Objects, 24 UST 2389; TIAS 7762; AFP 110-20, at 1 6-9 (1973). Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, Art I(1)(a), 14 UST 1313; TIAS 5433; 480 UNTS 43; AFP 110-20, at 8-3 (1963). 20 Arts. 17, 20, Chicago Convention. 21 Fedele, supra note 16, at 13.

22 Ibid.

23 See, e.g., Art VIII(1) of the Agreement in Implementation of Chapter VIII of the Agreement of Friendship and Cooperation Between the United States and Spain, 21 UST 2259; TIAS 6977; AFP 110-20, at 4-48 (1970); Arts. X(5), XV(3)(a), Facilities and Areas and the Status of United States Armed Forces in the Republic of Korea, 17 UST

1677; TIAS 6127 (1967), amalgamate for purposes of access and exit rights, freedom from landing charges and the like, "United States . . . aircraft operated by, for or under the control of the United States for official purposes. "Upon certification from the United States authorities, also exempted are aircraft of,

Corporations organized under the laws of the United States. . . present in the Republic of Korea solely for the purpose of executing contracts with the United States for the benefit of the United States armed forces.

Similar provisions are found in other status of forces and base rights agreements to which the United States is a party. The main purpose of such provisions is to secure for DOD charter aircraft the same rights of access, exit and freedom from landing fees and similar charges as are enjoyed by United States military aircraft under the particular agreement. The granting of such rights, however, does not mean that DOD charter aircraft thereby qualify as military aircraft or any other form of state aircraft. However, as the US Navy Law of Naval Warfare Manual states, "military aircraft" are only those operated by the military forces, bearing military markings, commanded by a member of the military forces and manned by a crew subject to military discipline. US Navy, NWIP 10-2, Law of Naval Warfare § 500(d) (1955), reprinted in 10 Whiteman 610 (1968).

24 US Navy, NWIP 10-2, Law of Naval Warfare § 500, nn 3-4 (1955), reprinted in 10 Whiteman 614 (1968).

25 Article 36, GWS; Article 39-40, GWS-SEA; Article 22, GC. See also paragraph 5(a), AFR 1604, (10 September 1971) and discussion paragraph 26e, this publication.

26 Authorities, supra note 17.

27 9 Whiteman 434 (1968).

28 See, e.g., NATO Status of Forces Agreement, Art. VII(3)(a)(ii); 4 UST 1792; TIAS 2846; 199 UNTS 67; AFP 110-20, at 4-2 (1951). Agreement Regarding Facilities and Areas and The Status of United States Armed Forces in Japan with Agreed Minutes, 11 UST 1652; TIAS 4510; 373 UNTS 248; AFP 110-20, at 4-19 (1960), Art XVII(3)(a)(ii) and Agreed Minutes thereto. See AFP 110-3, Air Force Civil Law Pamphlet, for discussion of applicable SOFA principles and rules.

29 The position of the United States Government on the effect of article 3 on the relationship of the Chicago Convention to state aircraft was stated as follows in 1964:

The Chicago Convention expressly excludes state aircraft from its scope and thus from the scope of ICAO responsibility. The United States intends that its state aircraft will follow the ICAO procedures set forth in Annex 2 to the greatest extent practicable; however, the