The international civil aviation is one of the sectors most adversely affected by the Russia-Ukraine conflict. In relation to the ongoing crisis, the United States of America, and the European Union on one side and the Russian Federation on the other side have taken unilateral measures, more commonly referred to as sanctions, against each other and restricting civil aviation activities between them. Currently, and in the broadest sense, the airspace of each side is closed to aircraft registered by the other side.

The history of aviation is, in a sense, the history of international agreements that were created as a result of the consensus of states. The most fundamental international legal document, known by its short name, the Chicago Convention of 1944, establishes the rules on how states can allow each other to use their airspace and can impose restrictions on such usage.

In Article 1 of the Chicago Convention, the contracting states recognize that every state has “complete and exclusive sovereignty” over the airspace above its territory. Accordingly, each signatory has the absolute right to open and close its airspace to others. Although it may seem reasonable at first to claim that states have the right to close their airspace to others as they wish based only on Article 1 of the Chicago Convention, in our opinion, especially in some respects, this interpretation may be both premature and lacks the holistic perspective.

In the Preamble of the Chicago Convention, it is stated that the consensus among states is based on the principle that "International Civil Aviation may be developed in a safe and orderly manner and that international air transport services may be established on the basis of equality of opportunity and operated in a soundly and economically." Accordingly, international civil aviation should be developed, be based on the principle of equality, and be operated economically.

According to Article 11 of the Chicago Convention, the rules governing the entry, departure, operation, and navigation of aircraft registered to the contracting state shall apply to aircraft of all contracting states without distinction as to nationality. In paragraph (g) of Article 44 of the Chicago Convention, avoiding discrimination between contracting states has been mentioned among the objectives of the International Civil Aviation Organization (ICAO). Other aims and objectives are: (a) ensure the safe and orderly growth of international civil aviation throughout the world; (b) encourage the arts of aircraft design and operation of peaceful purposes; (f) ensure that the rights of contracting states are fully respected and that every contracting state has a fair opportunity to operate international airlines. As per Article 15 of the Chicago Convention, every airport in a contracting state which is open to public use by its national aircraft shall likewise be open under uniform conditions to the aircraft of all the other contracting states, including the use of all air navigation facilities. Article 22 of the Chicago Convention stipulates that the contracting states facilitate and expedite the operations of aircraft registered to other contracting states. ICAO Assembly Resolution A40-9, Appendix A, Section 3 stipulates that member states should avoid adopting unilateral measures that may affect the development of international air transport. The Chicago Convention was followed by the International Air Services Transit Agreement, whereby each contracting state grants to the other contracting states (1) the privilege to fly across its territory without landing; (2) the privilege to land for non-traffic purposes. Both the Chicago Convention and the International Air Services Transit Agreement have been signed by many states. Bilateral or Multilateral Air Transport Agreements also allow states to use their airspace for third, fourth, and fifth freedom traffic rights. 

With the Russia-Ukraine crisis, the European Union revised its Regulation No. 833/2014 in 2022 and has prohibited any non-Russian-registered aircraft which is owned or chartered, or otherwise controlled by any Russian natural to land in, take off from or overfly the territory of the Union. Similarly, the US, through the Department of Transportation (DoT) Decision No. 2022-3-2 dated 2022, has prohibited Russian airlines and operators from using its airspace. It has become practically impossible to repair, maintain, overhaul, and insure aircraft associated with Russia as outlined under these unilateral measures. In addition, the Russian Federation has also closed its airspace to many countries. Another significant development in 2022 was when Bermuda, which under the 83bis Agreement with the Russian Federation held the airworthiness authorization and registration of many Russian aircraft, cancelled the airworthiness certificates of these aircraft, and demanded that the Russian Federation ground them. In response, the Russian Federation requested that Bermuda cancel the registration of these aircraft and suspended the 83bis Agreement with Bermuda. Despite Bermuda's refusal of this request, the Russian Federation registered these aircraft under its registry. However, an aircraft is only permitted to have one registration as per Article 18 of the Chicago Convention, because according to the preceding Article 17, the registration establishes the nationality of the aircraft, and establishing the nationality of an aircraft is essential for determining the law that will apply to it.

To summarize, in the history of International Civil Aviation, the system that was established by consensus between states and by subsequent bilateral or multilateral agreements have been suspended by Unilateral Measures, with the European Union and the US on one side and the Russian Federation on the other. This is not in the best interests of humans, let alone everything else, the closure of airspace causes additional flight distances, which in turn results in much more environmental pollution.

In addition, Article 26 of the Vienna Convention on the Law of Treaties, which is the fundamental legal document regulating the law on international treaties, deals with the principle of good faith, and parties to an international treaty must abide by it in good faith. According to Article 27 of the same convention, a party may not invoke the provisions of its internal law as justification for its failure to perform a treaty, while Article 60 allows a country that is party to a treaty to terminate or suspend its obligations to another party that has materially breached the treaty.

War and the harm its causes to civilians are unquestionably unacceptable when there are peaceful solutions. In addition, we consider that unilateral measures justifying war with the aim of putting other countries in an economically difficult situation, rather than addressing their security needs, are incompatible with the objectives of the Chicago Convention, the direction set accordingly, and the principles of the Vienna Convention on the Law of Treaties. International Civil Aviation, as the name implies, is civil; it exists to serve humanity and that is why it was developed, and freedom of travel and movement is a fundamental right. We believe that restrictions imposed by unilateral measures ultimately have a negative impact on civilians and we hope that parties will take the necessary relief measures under the leadership of ICAO with full participation, with Russia rejoining the Council