1. The first sentence of Rule 170 (a) is based on Art. 40 of the HRAW (“Belligerent military aircraft are forbidden to enter the jurisdiction of a neutral state”) and reemphasizes the principle of inviolability of neutral airspace. Accordingly, any entry into neutral airspace by belligerent military aircraft or missiles constitutes a violation of the Neutral’s inviolability.
2. However, in view of the recent development of international law regarding the rights of transit and archipelagic sea lanes passage, the airspace above neutral international straits and archipelagic sea lanes remains open at all times to belligerent aircraft, including armed military aircraft. Of course, such passage must be continuous and expeditious and must be undertaken in the normal mode of flight of the aircraft involved. Belligerent aircraft must refrain from acts of hostility while in transit, but may engage in activities that are consistent with their security and the security of accompanying surface and subsurface forces. The Neutral is under an obligation not to suspend, hamper or otherwise impede the right of transit passage or the right of archipelagic sea lanes passage (see Para. 7.3.6 of NWP^[801] and Para. 7.3.9 of NWP^[802] ). See also paragraph 8 of the Commentary on Rule 1 (a).
3. UAVs/UCAVs also enjoy the rights of transit or of archipelagic sea lanes passage. Therefore, they may transit the airspace above an international strait or an archipelagic sea lane continuously and expeditiously. They are, however, prohibited to loiter within that airspace for purposes other than transit.
4. Warships exercising the rights of transit passage or of archipelagic sea lanes passage are entitled to launch and to take on board UAVs and UCAVs. If UAVs are a necessary element of a warship’s force protection, they may be employed even if they do not transit “continuously and expeditiously”, provided that the use of such UAVs is “incidental” to the warship’s “normal mode”.^[803]
5. The prohibition to enter neutral airspace does not apply to belligerent military aircraft in distress (see Rule 172 (a) (i)).
6. For the entry of belligerent medical aircraft into neutral airspace, see Rule 84 and Rule 85.

801. Para. 7.3.6 of NWP (“Neutral international straits”): “Customary international law as reflected in the 1982 LOS Convention provides that belligerent and neutral surface ships, submarines, and aircraft have a right of transit passage through, over, and under all straits used for international navigation. Neutral nations cannot suspend, hamper, or otherwise impede this right of transit passage through international straits. Belligerent forces transiting through international straits overlapped by neutral waters must proceed without delay, must refrain from the threat or use of force against the neutral nation, and must otherwise refrain from acts of hostility and other activities not incident to their transit. Belligerent forces in transit may, however, take defensive measures consistent with their security, including the launching and recovery of military devices, screen formation steaming, and acoustic and electronic surveillance, and may respond in self-defense to a hostile act or hostile intent. Belligerent forces may not use neutral straits as a place of sanctuary or as a base of operations, and belligerent warships may not exercise the belligerent right of visit and search in those waters.”
802. Para. 7.3.9 of NWP (“Neutral airspace and duties”): “(1) Neutral territory extends to the airspace over a neutral nation’s lands, internal waters, archipelagic waters (if any), and territorial sea. Belligerent military aircraft are forbidden to enter neutral airspace with the following exceptions: (a) The airspace above neutral international straits and archipelagic sea lanes remains open at all times to belligerent aircraft, including armed military aircraft, engaged in transit or archipelagic sea lanes passage. Such passage must be continuous and expeditious and must be undertaken in the normal mode of flight of the aircraft involved. Belligerent aircraft must refrain from acts of hostility while in transit, but may engage in activities that are consistent with their security and the security of accompanying surface and subsurface forces. … (2) Neutral nations have an affirmative duty to prevent violation of neutral airspace by belligerent military aircraft, to compel offending aircraft to land, and to intern both offending aircraft and crew. Should a neutral nation be unable or unwilling to prevent the unlawful entry or use of its airspace by belligerent military aircraft, belligerent forces of the other side may undertake such self-help enforcement measures as the circumstances may require.”
803. Art. 39 (1) and (3) of UNCLOS (“Duties of Ships and Aircraft during Transit Passage”): “(1) Ships and aircraft, while exercising the right of transit passage, shall: (a) proceed without delay through or over the strait; (b) refrain from any threat or use of force against the sovereignty, territorial integrity or political independence of States bordering the strait, or in any other manner in violation of the principles of international law embodied in the Charter of the United Nations; (c) refrain from any activities other than those incident to their normal modes of continuous and expeditious transit unless rendered necessary by force majeure or by distress; (d) comply with other relevant provisions of this Part. … (3) Aircraft in transit passage shall: (a) observe the Rules of the Air established by the International Civil Aviation Organization as they apply to civil aircraft; State aircraft will normally comply with such safety measures and will at all times operate with due regard for the safety of navigation; (b) at all times monitor the radio frequency assigned by the competent internationally designated air traffic control authority or the appropriate international distress radio frequency.”
     Art. 54 of UNCLOS declares Art. 44 to be applicable to archipelagic sea lanes passage, see fn. 732.

The obligation to prevent or to terminate violations of its neutral status implies that the Neutral must be sufficiently aware of what is occurring both within and in the vicinity of its national airspace. This denotes an obligation to use all available means, including radar and other electronic equipment, with a view to monitoring on a constant basis the national and adjacent airspace.

1. A Neutral is bound to use all the means at its disposal to prevent belligerent military aircraft from entering its jurisdiction (see Rule 170 (b)).
2. Rule 170 (c) is derived from Art. 25 of the 1907 Hague Convention (XIII),^[804] as well as from Art. 42^[805] and Art. 47 of the HRAW.^[806]
3. The Neutral whose national airspace has been violated by an intruding belligerent military aircraft is obliged to terminate that violation. If possible, the intruding aircraft ought to be compelled to land. But, if it does not comply, the Neutral is entitled to shoot it down. Should the aircraft land, as required, the Neutral must intern the aircraft and its crew for the duration of the international armed conflict. This obligation derives from Art. 42 of the HRAW^[807] and customary international law.^[808]
4. Whenever members of the armed forces of a Belligerent Party enter neutral territory, they have to be interned by the Neutral for the duration of the international armed conflict. This general norm applies irrespective of the circumstances in which aircrews enter the territory of a Neutral. According to Art. 43 of the HRAW “[t]he personnel of a disabled belligerent military aircraft rescued outside neutral waters and brought into the jurisdiction of a neutral state by a neutral military aircraft and there landed shall be interned.”
5. Parachutists from an aircraft in distress (see Section T), landing in neutral territory (for whatever reason, e.g., due to wind currents), must also be interned. If such parachutists in distress land in international waters, and are rescued by neutral vessels or aircraft, they must equally be interned for the duration of the international armed conflict.

804. Art. 25 of Hague Convention (XIII): “A neutral Power is bound to exercise such surveillance as the means at its disposal allow to prevent any violation of the provisions of the above Arts. occurring in its ports or roadsteads or in its waters.”
805. Art. 42 of the HRAW: “A neutral government must use the means at its disposal to prevent the entry within its jurisdiction of belligerent military aircraft and to compel them to alight if they have entered such jurisdiction. A neutral government shall use the means at its disposal to intern any belligerent military aircraft which is within its jurisdiction after having alighted for any reason whatsoever, together with its crew and the passengers, if any.”
806. Art. 47 of the HRAW: “A neutral state is bound to take such steps as the means at its disposal permit to prevent within its jurisdiction aerial observation of the movements, operations or defenses of one belligerent, with the intention of informing the other belligerent.”
807. Art. 42 of the HRAW, see fn. 805.
808. The final sentence of the first subpara. of Para. 7.3.1. of NWP reads: “Belligerent troops that enter neutral territory must be disarmed and interned until the end of the armed conflict.”

Rule 171 specifies, in a non-exhaustive manner, the general prohibition contained in Rule 166 and in Rule 167 (a).

The prohibition of Rule 171 (a) is based on Art. 2 of the 1907 Hague Convention (XIII)^[809] and on Art. 39 of the HRAW.^[810] Attacks on and capture of persons or objects are belligerent acts which, if committed in neutral airspace, constitute a breach of the inviolability of neutral territory. This means that the activities referred to in Section D or in Section U, cannot be exercised in neutral airspace.

809. Art. 2 of Hague Convention (XIII): “Any act of hostility, including capture and the exercise of the right of search, committed by belligerent warships in the territorial waters of a neutral Power, constitutes a violation of neutrality and is strictly forbidden.”
810. Art. 39 of the HRAW: “Belligerent aircraft are bound to respect the rights of neutral Powers and to abstain within the jurisdiction of a neutral state from the commission of any act which it is the duty of that state to prevent.”

1. Rule 171 (b) is based on Art. 5 of the 1907 Hague Convention (XIII).^[811] In contrast to the situation envisioned in Rule 171 (a), Rule 171 (b) posits a deployment of forces in neutral airspace or territory in order to attack enemy targets located outside such airspace or territory.
2. The term “base of operations” in neutral airspace is to be interpreted in broad terms. Thus, for example, a UCAV loitering in neutral airspace before launching a missile against belligerent target is acting in breach of Rule 171 (b).

811. Art. 5 of Hague Convention (XIII): “Belligerents are forbidden to use neutral ports and waters as a base of naval operations against their adversaries, and in particular to erect wireless telegraphy stations or any apparatus for the purpose of communicating with the belligerent forces on land or sea.”

1. Rule 171 (c) is based on Art. 2 of the 1907 Hague Convention (XIII),⁸¹² which prohibits the exercise of prize measures (see Section U) within neutral territory.
2. “Neutral territory” as used in Rule 171 (c) encompasses not only neutral airspace but also land territory or sea areas covered by the territorial sovereignty of the Neutral.
3. A Belligerent Party is not allowed to intercept any aircraft within neutral airspace, even with a view to forcing it to land outside the neutral territory.
4. Obviously, there is a certain overlap in terms of “capture” between Rule 171 (a) and Rule 171 (c). The reason is that Rule 171 (c) refers not merely to capture of aircraft, but also to capture of vessels. The Group of Experts felt that it was important to ensure that all aspects of capture are covered either in Rule 171 (a) or in Rule 171 (c).

812. Art. 2 of Hague Convention (XIII), see fn. 809.

1. The purpose of Rule 171 (d) is to emphasize that any “use of military force” in neutral territory, as well as any activity “contributing to the war-fighting effort” of the enemy, constitutes a violation of neutral territory even if such use or contribution does not amount to an act prohibited by Rule 171 (a) − (c).
2. An illustration of such activity is the transmission of data for targeting or other military purposes, which must be distinguished from the use of neutral airspace or territory as a base of operations prohibited under Rule 171 (b). The transmission of military data from neutral territory by a Belligerent Party must be considered a violation of neutral territory and airspace even if it is not performed for attack, targeting or other purposes.
3. Rule 171 (d) has to be read in conjunction with Rule 167 (b), according to which the “use for military purposes of a public, internationally and openly accessible network, such as the Internet” will not constitute a violation of neutrality if “part of this infrastructure is situated within the jurisdiction of a neutral”.
4. Combat search and rescue operations are genuinely military in character (see Rule 86) and, thus, constitute a violation of neutrality. The fact that such operations are aimed at the rescue of combatants who may be wounded, sick or shipwrecked (see Rule 16 (a)) is irrelevant Combatants present in neutral territory — whatever the reason for their presence — must be interned by the Neutral for the duration of the international armed conflict (see Rule 170 (c), as well as the second paragraph of Art. 42 of the HRAW^[813] and Art. 43 of the HRAW^[814] ).

813. Art. 42 of the HRAW, see fn. 805.
814. Art. 43 of the HRAW, see Para. 4, Rule 170 (c), Section X.

Rule 172 (a) is a specification of the general prohibition laid down in the first sentence of Rule 170 (a). The prohibition for belligerent military aircraft to enter neutral airspace is based on Art. 40 of the HRAW,^[815] and it is a necessary corollary to the inviolability of neutral territory.

815. Art. 40 of the HRAW, see fn. 771.

1. Following the general obligation to render assistance to those who are in distress in the air, a Neutral may allow a belligerent military aircraft in distress to land in its territory. Such permission may not be considered a violation of neutrality by the other Belligerent Party.
2. However, the Neutral is not allowed to permit Belligerent Parties the use of its airspace for transit purposes. The Neutral is obliged to require any belligerent military aircraft to land, if necessary by the use of appropriate force. For the duration of the international armed conflict, the belligerent military aircraft and its crew may not leave the Neutral’s territory, and the crew must be interned in order to prevent them from re-engaging in the hostilities.

Rule 172 (a) (ii) safeguards the customary rights of transit passage and of archipelagic sea lanes passage as recognized in Rule 170 (a).

1. Entry by belligerent military aircraft into neutral airspace is not prohibited if the aircrews intend to capitulate to the Neutral. Should that occur, the Neutral is under an obligation to intern the aircrews for the duration of the international armed conflict (see Rule 172 (b)).
2. Rule 172 (a) (iii) deals with the issue of military personnel giving themselves up. The term “capitulation” used here is reserved for such act taking place vis-à-vis a Neutral. When military personnel give themselves up to the enemy, the expression used in this Manual is “surrender” (see Section S). As to the modalities of capitulation, see Rule 172 (b).

1. Capitulation, as required by Rule 172 (a) (iii), must not be abused by turning the Neutral territory into a “base of operations”. Hence, the Neutral must insist on the capitulating aircraft landing within its territory rather than transiting, and must then intern both the aircraft and its crew for the duration of the international armed conflict. The rationale of this Rule is that, if the aircraft or aircrews were allowed to leave the neutral territory, it might re-engage in the hostilities.
2. Any act of resistance or deliberate non-compliance is to be considered a “hostile act” and, therefore, sufficient ground for the Neutral to attack the aircraft. In that case, prior warnings or periods of grace are not required.

1. The first sentence of Rule 173 is based on Art. 45 of the HRAW,^[816] Art. 7 of the 1907 Hague Convention (V),^[817] and Art. 7 of the 1907 Hague Convention (XIII).^[818]
2. Without prejudice to an embargo decided upon by the UN Security Council, Rule 173 exclusively applies to private activities and not to government activities. Accordingly (see Art. 44 of the HRAW), “[t]he supply in any manner, directly or indirectly, by a neutral government to a belligerent Power of aircraft, parts of aircraft, or material, supplies or munitions required for aircraft is forbidden.”
3. The distinction between public and private export and transit activities has been recognized by Art. 6^[819] , Art. 7^[820] and Art. 8^[821] of the 1907 Hague Convention (XIII), as well as by Art. 44,^[822] Art. 45^[823] and Art. 46 of the HRAW.^[824] There has nevertheless been some scepticism as to its continued validity. It has been argued that,^[825] in an era when exports of military and “dual-use” goods are subject to State regulation, it is no longer correct to say that Neutrals are at liberty to allow private exports of such goods in an unregulated manner. Still, the majority of the Group of Experts has not been able to confirm on the basis of State practice that a modification of the traditional rule relating to the distinction between public and private exports has occurred. State practice clearly gives evidence of an increasing control of exports of arms and other military equipment by States. However, it gives no evidence that States consider themselves obliged by the law of neutrality to exercise such control. It seems that this is only a policy preference and not an expression of opinio juris.

816. Art. 45 of the HRAW: “Subject to the provisions of Article 46, a neutral Power is not bound to prevent the export or transit on behalf of a belligerent or aircraft, parts or aircraft, or material, supplies or munitions for aircraft.”
817. Art. 7 of the 1907 Hague Convention (V): “A neutral Power is not called upon to prevent the export or transport, on behalf of one or other of the belligerents, of arms, munitions of war, or, in general, of anything which can be of use to an army or a fleet.”
818. Art. 7 of the 1907 Hague Convention (XIII): “A neutral Power is not bound to prevent the export or transit, for the use of either belligerent, of arms, ammunition, or, in general, of anything which could be of use to an army or fleet.”
819. Art. 6 of the 1907 Hague Convention (XIII): “The supply, in any manner, directly or indirectly, by a neutral Power to a belligerent Power, of war-ships, ammunition, or war material of any kind whatever, is forbidden.”
820. Art. 7 of the 1907 Hague Convention (XIII), see fn. 817.
821. Art. 8 of the 1907 Hague Convention (XIII): “A neutral Government is bound to employ the means at its disposal to prevent the fitting out or arming of any vessel within its jurisdiction which it has reason to believe is intended to cruise, or engage in hostile operations, against a Power with which that Government is at peace. It is also bound to display the same vigilance to prevent the departure from its jurisdiction of any vessel intended to cruise or engage in hostile operations, which had been adapted entirely or partly within the said jurisdiction for use in war.”
822. Art. 44 of the HRAW: “The supply in any manner, directly or indirectly, by a neutral government to a belligerent Power of aircraft, parts of aircraft, or material, supplies or munitions required for aircraft is forbidden.”
823. Art. 45 of the HRAW, see fn. 816.
824. Art. 46 of the HRAW: “A neutral government is bound to use the means at its disposal: (1) To prevent the departure from its jurisdiction of an aircraft in a condition to make a hostile attack against a belligerent Power, or carrying or accompanied by appliances or materials the mounting or utilization of which would enable it to make a hostile attack, if there is reason to believe that such aircraft is destined for use against a belligerent Power. (2) To prevent the departure of an aircraft the crew of which includes any member of the combatant forces of a belligerent Power. (3) To prevent work upon an aircraft designed to prepare it to depart in contravention of the purposes of this Article ; On the departure by air of any aircraft despatched by persons or companies in neutral jurisdiction to the order of a belligerent Power, the neutral government must prescribe for such aircraft a route avoiding the neighborhood of the military operations of the opposing belligerent, and must exact whatever guarantees may be required to ensure that the aircraft follows the route prescribed.”
825. Para. 1112 of the German ZDv: “State practice has modified the former convention rule that a neutral state is not bound to prohibit export and transit of war material by private persons for the benefit of one of the parties to the conflict (Art. 7 HC V). To the extent that arms export is subject to control by the state, the permission of such export is to be considered as a non-neutral service.”

1. This Rule is based on Art. 46 (1) of the HRAW.^[826]
2. Rule 173 (a) is historically an outgrowth of a similar prohibition relating to warships, having its roots in the famous 1872 Arbitral Award in the “Alabama” case.^[827]
3. The words “in a condition to make a hostile attack” mean that the aircraft is fuelled, armed and manned, ready for immediate hostile action after departure.

826. Art. 46 (1) of the HRAW, see fn. 824.
     See also Art. 8 of the 1907 Hague Convention (XIII), see fn. 821.
827. See Alabama Claims Award (1872), 1 History and Digest of the International Arbitrations to which the United States Has Been a Party 653 (J.B. Moore ed., 1898).

1. This Rule is based on Art. 46 (2) of the HRAW.^[828]
2. Members of the armed forces of a Belligerent Party must be interned by the Neutral for the duration of the international armed conflict (see Rule 170 (c)). It follows that the Neutral must prevent their departure from its jurisdiction.
3. The category “members of the armed forces of a Belligerent Party” is comprehensive. It includes not only crews of military aircraft, but also passengers and crews of civilian aircraft who are members of those armed forces.

828. Art. 46 (2) of the HRAW, see fn. 824.

1. This Rule, when considered in its entirety, applies only to neutral civilian aircraft. Having said that, it must be understood that other neutral aircraft — military or other State aircraft — may not engage in any of the activities enumerated in Rule 174 (b); Rule 174 (c); Rule 174 (d) and in Rule 174 (f). If they do, they become military objectives that may be attacked without prior warning. However, unlike neutral civilian aircraft, both Rule 174 (a) and Rule 174 (e) are inapplicable to neutral military aircraft and to other neutral State aircraft. Such aircraft benefit from the sovereign immunity of the Neutral that must be respected by Belligerent Parties (see also paragraph 2 of the Commentary on Rule 48 (b) and paragraph 5 of the Commentary to Rule 54). Consequently, they cannot be intercepted, diverted, or inspected when suspected of carrying contraband, and they do not have to comply with orders of military authorities of a Belligerent Party (except where aerial blockade is concerned, see Rule 155).
2. Neutral civilian aircraft are protected under the law of neutrality, as long as they are engaged in their normal and innocent role. Nevertheless, if they engage in acts which make an effective contribution to the enemy’s military action and if their destruction, capture or neutralization offers a definite military advantage in the circumstances ruling at the time, they lose their protected status and become military objectives.
3. Neutral civilian aircraft, if engaged in one of the activities enumerated in Rule 174, lose their neutral protected status and become liable to attack,^[829] subject to Sections D and G.
4. Rule 174 is without prejudice to the right of Belligerent Parties to establish an aerial (or naval) blockade against the enemy (see Section V). According to Rule 156, neutral civilian aircraft believed on reasonable grounds to be breaching, or attempting to breach, an aerial blockade may be intercepted, diverted, forced to land and captured. If they clearly resist interception, or fail to comply with an order to land, they are at risk of attack after prior warning.
5. Rule 174 does not apply to any of the categories covered in Section J, i.e. civilian airliners and aircraft granted safe conduct (such as cartel aircraft). For the parallel provision, see Rule 63.
6. Rule 174 must be read against the background of Rule 27 pertaining to attacks against enemy aircraft other than military aircraft. Rule 174 (b) − (f) is textually identical to Rule 27 (a) − (e). It is only Rule 174 (a) which is specific to neutral civilian aircraft.
7. The status of neutral civilian aircraft must always be borne in mind. In addition to their civilian character, there is the extra added dimension of their being neutral. On both grounds, a Belligerent Party must not rush to the conclusion that a neutral civilian aircraft constitutes a military objective.
8. The following activities relate only to use and intended future use, and are therefore subject to the application of Rule 22 (c) and Rule 22 (d).

829. Para. 70 of the SRM/ACS: “Civil aircraft bearing the marks of neutral States may not be attacked unless they: (a) are believed on reasonable grounds to be carrying contraband, and, after prior warning or interception, they intentionally and clearly refuse to divert from their destination, or intentionally and clearly refuse to proceed for visit and search to a belligerent airfield that is safe for the type of aircraft involved and reasonably accessible; (b) engage in belligerent acts on behalf of the enemy; (c) act as auxiliaries to the enemy’s armed forces; (d) are incorporated into or assist the enemy’s intelligence system; or (e) otherwise make an effective contribution to the enemy’s military action, e.g. by carrying military materials, and, after prior warning or interception, they intentionally and clearly refuse to divert from their destination, or intentionally and clearly refuse to proceed for visit and search to a belligerent airfield that is safe for the type of aircraft involved and reasonably accessible.”
     Similar language can be found in Para. 12.43.1 of the UK Manual.

1. Rule 174 (a) is based on the second sentence of Art. 50 of the HRAW, which provides: “Refusal, after warning, to obey such orders to alight or to proceed for visit and search to such a locality for examination exposes an aircraft to the risk of being fired upon.” This corresponds with customary international law (see Para. 70 (a) of the SRM/ACS).^[830]
2. Neutral civilian aircraft flying outside neutral airspace and that are carrying contraband on board, may be intercepted, inspected, diverted and / or captured (see Rule 137). If they intentionally and clearly refuse to comply with orders to divert or proceed for inspection, this will render them a military objective.
3. A neutral civilian aircraft does not become a military objective only because it carries contraband. It is the intentional and clear refusal of such an aircraft to divert from its destination or to proceed for inspection that may render it a military objective.

830. Para. 70 (a) of SRM/ACS, see fn. 829.

The language of Rule 174 (b) is identical to that appearing in Rule 27 (a). See the Commentary on the latter as well as Para. 70 (b) of SRM/ACS.^[831]

831. Para. 70 (b) of SRM/ACS see fn. 829.

The language of Rule 174 (c) is identical to that appearing in Rule 27 (b). See the Commentary on the latter and see Para. 70 (c) of SRM/ACS.^[832]

832. Para. 70 (c) of SRM/ACS, see fn. 829.

If neutral civilian aircraft engage — in support of the enemy armed forces — in reconnaissance, early warning, surveillance or command, control and communications mission, they may be considered as having become incorporated into the enemy’s intelligence system under Rule 174 (d). The language of Rule 174 (d) is identical to that appearing in Rule 27 (c). See the Commentary on the latter and Para. 70 (d) of SRM/ACS. ^[833]

833. Para. 70 (d) of SRM/ACS, see fn. 829.

Neutral civilian aircraft are under an obligation to comply with the orders of a Belligerent Party. If a neutral civilian aircraft does not comply with such orders, the Belligerent Party is entitled to use such force as is necessary to overcome the resistance. The language of this Rule 174 (e) is identical to that appearing in Rule 27 (d). See the Commentary on the latter.

Rule 174 (f) is a residual provision in that it covers situations in which a neutral civilian aircraft makes an effective contribution to the enemy’ military actions that are not dealt with in Rule 174 (a) − (d). See Para. 70 (e) of SRM/ACS.^[834] The language of Rule 170 (f) is identical to that appearing in Rule 27 (e). See the Commentary on the latter.

834. Para. 70 (e) of SRM/ACS, see fn. 829.

1. While the fact that a civilian aircraft bears the marks of an enemy State is conclusive evidence of its enemy character (see Rule 144), bearing the marks of a Neutral does not provide such conclusive evidence. Therefore, Rule 175 merely contains a presumption of the neutral character of civilian aircraft bearing neutral marks.
2. As laid down in the second sentence of Rule 144, enemy character of a civilian aircraft can also be determined by registration, ownership, charter or other appropriate criteria. According to Rule 145, civilian aircraft bearing no marks are presumed to have enemy character for the purposes of capture and prize. If there merely are grounds for suspicion that a civilian aircraft has enemy character, Rule 146 applies.