Not Just a Bilateral Matter: Targeting Airports Under International Law and Erga Omnes Partes Obligations

[Narek Abgaryan is a legal professional specializing in public international law with expertise in international humanitarian law and the law of international treaties, currently focused on promoting international law and legal education in Armenia.

Davit Khachatryan is an international law expert and lecturer specializing in public international law, alternative dispute resolution, investment law, international humanitarian law, and security.]

Much has been written about the legality of the operations “Roaring Lion” and “Epic Fury” under international law, and most particularly, jus contra bellum. However, while under the auspices of the UN Charter, the situation can be unambiguous, when we turn to International humanitarian law (IHL) and human rights law, many more debates arise.

Since the beginning of the recent escalation, Iran has been targeting several Gulf states as well as Jordan in response to US and Israeli armed attacks on its territory. Tehran denied responsibility in several other incidents, including drone attacks on Azerbaijan’s Nakhchivan region and later ballistic missile intrusions into Turkish airspace. The announced aim of such strikes was to target US military compounds. The latest escalation, beginning in February, has brought with it a discernible shift: more and more targets that are, on their face, civilian objects. This includes hotels, ports, airports, and other civilian objects in many neighboring countries to Iran, including but not limited to the United Arab Emirates, Bahrain, and Kuwait. While commenting on such strikes, Iran’s foreign minister explained that the reason behind such strikes was that US forces had relocated to urban areas.

As each armed attack committed against a civilian object should require a proper investigation under international humanitarian law, this paper aims to focus on attacks on civilian airports in general, and the broader consequences such attacks may have that go beyond international humanitarian law.

Airports Under the Law of Targeting

The ongoing conflict between Iran, Israel, and its spillover into several Gulf states, including the UAE, constitutes an international armed conflict (IAC) within the meaning of common Article 2 of the Geneva Conventions, triggered by the resort to armed force between states (Tadić, para. 70). IHL applies accordingly. The states involved in or directly affected by this conflict, among them Iran, Israel, and the UAE, are not parties to Additional Protocol I (API). Nonetheless, they are bound by customary international humanitarian law, ICRC Customary IHL Rules 7 and 8, which limit attacks to military objectives and define them in terms reflected in Article 52 of AP I.

Civilian objects may not be attacked. An object qualifies as a military objective under Article 52(2) if two cumulative conditions are met: it makes an effective contribution to military action by its nature, location, purpose, or use; and its destruction, capture, or neutralisation offers a definite military advantage in the circumstances ruling at the time. Both prongs must be satisfied simultaneously.

Civilian airports, by nature, are civilian infrastructure. Historically, they are routinely militarised in armed conflict, used for troop movements, logistics, and force projection. This contingent susceptibility to military use, however, does not alter their default legal status. Article 52(3) is explicit: where doubt exists, an object normally dedicated to civilian purposes is presumed not to constitute a military objective. The burden falls on the attacking party to establish that the conditions of Article 52(2) are met at the time of the attack.

The Dual-Use Problem

Infrastructure that serves both civilian and military functions has long presented the hardest targeting questions under IHL. Ports, bridges, railways, energy grids, and telecommunications networks are the canonical examples, objects whose civilian utility is substantial and whose military utility is contingent, context-dependent, and often simultaneous. The law does not categorically protect them, nor does it categorically expose them. Their status turns entirely on whether the Article 52(2) conditions are met at the time of the attack.

Where do civilianairports) sit in this taxonomy? Airports have been treated as military objectives in virtually every major conflict of the past century. This alone, however, does not establish a presumption of dual-use status.  Military use must be demonstrated anew in each instance, against the baseline presumption of civilian character that Article 52(3), and ICRC Customary IHL Rule 9 expressly maintain.

For example, Dubai International Airport (DXB) is simultaneously the world’s busiest passenger hub, a critical cargo corridor, and a regional centre for aviation fuel supply, maintenance, and air traffic management. On the other hand, the Gulf hosts a dense network of US-allied military facilities. Nevertheless, Article 52(2) requires effective contribution to military action by actual nature, location, purpose, or use; not by proximity to allied bases or theoretical susceptibility to military activation. This airport is so systemically important to global aviation and trade that its disruption constitutes, in itself, a form of strategic pressure. IHL refuses to treat global economic significance as a basis for military objective status.

Proportionality and Precautions

Even if the targeted airports were to qualify as military objectives, the proportionality rule would remain fully operative. Article 57(2)(a)(iii) AP I, reflecting ICRC Customary IHL Rule 14, prohibits attacks expected to cause incidental civilian harm that is excessive in relation to the concrete and direct military advantage anticipated.

The proportionality assessment is not straightforward to resolve against Iran. Workers were injured, the terminal sustained minor damage. Flights were suspended temporarily. As a matter of strict proportionality doctrine, this is not obviously excessive. The downstream disruptions were real: flight cancellations, stranded passengers, cascading effects on global aviation. But IHL does not currently recognise these wider economic and logistical consequences as legally cognizable incidental harm for proportionality. Stretching the doctrine to capture them would be analytically dishonest.

Where Iran’s conduct is more clearly vulnerable is on precautions. ICRC Customary IHL Rule 15 requires verification of target status, choice of means minimising civilian harm, and restraint where uncertainty remains. Striking a presumptively civilian object, the largest international transit hub whose military character was, at best, unestablished, fails that standard regardless of how the proportionality calculus resolves.

Targeting airports and Erga Omnes Partes Obligations

After the recent escalation of hostilities, Iranian attacks on major regional air transportation hubs created chaos, resulting in the cancellation of thousands of flights for the next few weeks. For many tourists, a long-awaited vacation became a nightmare, with no certainty of return to their homeland and loved ones. While airports are objects located within a country’s territory, their functions create links between cities, countries, and continents; therefore, even the temporary closure of one airport affects numerous passengers around the world. Considering the series of airport strikes targeting Kuwait International Airport, Bahrain International Airport, as well as Zayed International Airport, and Dubai International Airport in the UAE, one may argue that even if considered US-Israeli assets or support platforms in the region, several treaty-based restrictions should make Iran think twice from the perspective of the country’s international legal obligations.

Under international aviation law, Iran is a party to several multilateral treaties that guarantee the protection of international airspace and foster inter-state cooperation in international aviation. While the general framework and principles of the field are mainly established under the 1944 Convention on International Civil Aviation (ICAO Convention), of primary interest for our case is the 1971 Montreal Convention and its 1988 supplementary Protocol for the suppression of unlawful acts of violence at airports serving international civil aviation.

Unlike the Chicago Convention framework, which is primarily aimed toward the development of civil aviation, the Montreal regime is dedicated to safeguarding international civil aviation by legally protecting it from acts of violence and disruption. While the 1971 Convention in Article 1 addresses offences committed against persons on board of aircraft or the aircraft itself, as well as air navigation facilities (which can apply to our cases), the 1988 Protocol further extends application of the treaty to offences (both intentional and unintentional) that destroys or seriously damages the facilities of an airport serving international civil aviation or aircraft not in service located thereon or disrupts the services of the airport.

The Montreal regime identifies the above-mentioned attacks as falling within the scope of the documents and constituting prohibited behaviour that can, in its turn, result in the partial or complete paralysis of the airport’s functioning. While at first sight, the phrase “any person” in Article 1 of the Convention can be attributable to physical persons only, the further reading of the Convention stipulates in Article 10 that signatory states bear also a responsibility to take all practicable measure for the purpose of preventing the offences mentioned in Article 1. Furthermore, Articles 5 and 7 of the Convention create a framework for jurisdiction and a subsequent mutually exclusive prosecute or extradite obligation.

In our scenario, the conduct of attacking airports is attributable to a state. If targeted airports are not classified under the lex specialis (IHL) paradigm as legitimate military objectives (which is most possibly the case), then the conduct should be considered unlawful under both the IHL and the Montreal regime in a narrow sense, where, the breach arises a fortiori as under the Convention and its Protocol any state cannot be allowed to engage in conduct which it should simultaneously criminalize and suppress.

Turning to Erga omnes partes, these obligations are non-bilateral in their nature and should be owed to all parties of a multilateral treaty in general. While the ICJ jurisprudence addressed these obligations in relation to the Genocide Convention and the Convention against Torture, there is a position gaining momentum that the application of the mentioned type of obligations can be extended to cover not only human rights treaties, but also agreements from other branches, as well as beyond treaties that are non-reciprocal in character. Air or naval navigation agreements, multilateral trade treaties can be considered of a nature that creates erga omnes partes obligations.

Additionally, the same logic applied by the Court in Belgium v. Senegal (para. 69) is applicable here, as the 1988 Montreal document similarly calls on the state parties to apply the rule of prosecution or extradition for all offences mentioned in Article 1, paragraph 1 bis of the Protocol. Even though the primary object and purpose of the Montreal Convention and its Protocol are not directly aimed at human rights protection, they are not limited to the protection of individual state interests as well. They would rather extend to sheltering the security of air navigation and international civil aviation as a global mechanism. Therefore, the maxim aut dedere aut judicare encapsulates a shared interest of all states that are parties to the Convention and its Protocol, including Iran, Bahrain, Kuwait, and the UAE. Airports discussed here are not solely aerodromes but major transit hubs transporting millions of passengers annually and connecting the Middle East to almost every continent. The disruption of their activities paralyzes not only the Gulf region but also creates numerous human rights issues for persons unfortunate to travel through these hubs during the period of Iran’s attacks. It is, therefore, logical to think that these strikes violate not only obligations vis-à-vis affected Gulf countries but also other parties to the Montreal documents, endangering the air security architecture.

Photo attribution: by Bao Menglong on Unsplash