An air services agreement (also known as the ATA or ASA) is a bilateral agreement that allows international commercial air services between signatories. Air Services Agreements (ASAs) are formal contracts between countries – Memorandums of Understanding (Memorandum of Understanding) and formal diplomatic notes. It is not mandatory to have an ASA for the operation of international services, but cases where contract-free services exist are rare. The World Air Services Agreements (WASA) Database is the most comprehensive database of air agreements in the world. The summaries of the provisions have no formal interpretation of the intentions of the parties to the air transport agreements or the content of those agreements. Abstracts therefore do not replace the actual text of the agreement. One of the first AAS after World War II was the Bermuda Agreement, signed in 1946 by the United Kingdom and the United States. The characteristics of this agreement have become models for the thousands of agreements that were to follow, although in recent decades some of the traditional clauses of these agreements have been amended (or “liberalized”) in accordance with the “open skies” policy of some governments, particularly the United States.  Conduct comparative analyses of air services agreements; The bilateral system is based on the Chicago Convention and related multilateral treaties. The Chicago Convention was signed in December 1944 and has governed international air services ever since. the convention also contains a number of annexes covering issues such as aviation safety, safety monitoring, seaworthiness, navigation, environmental protection and facilities (acceleration and departure at airports). In 1913, a bilateral exchange of notes  between Germany and France was signed in the first agreement to provide airship services.
Rules for the registration process to be found in doc 6685 – ICAO registration rules for air agreements and agreements. The inclusion of agreements in the WASA does NOT replace the requirement for states to register these agreements or amendments in accordance with Article 83 of the Chicago Convention. In principle, all ASAs should be registered by the DAGMAR International Civil Aviation Organization of the ICAO air agreements and agreements database, but this source is not absolutely complete. WASA is an expanded online platform that replaces earlier versions of the Database of the World`s Air Services Agreement, published as ICADoc 9511 in paper and then IN CD-ROM format. ICAO`s WASA as a unique analytical tool for regulators, airlines and other aviation stakeholders: to learn more about wasa and purchasing opportunities, visit the ICAO Civil Aviation Data Solutions (iCADS) portal to view the wasa product page.