Why are international airline traffic rights usually arranged through bilateral agreements?

International airline traffic rights are primarily arranged through bilateral agreements because efforts to establish a widely acceptable multilateral framework for these commercial privileges have been unsuccessful.1

This reliance on bilateralism stems from the fundamental principle of airspace sovereignty, which dictates that every state holds complete and exclusive authority over the airspace above its territory. Because states have the right to regulate the entry of foreign aircraft, they prefer to negotiate specific, reciprocal terms directly with other nations.1

These bilateral agreements serve several critical functions:
* Route Definition: They fix the specific routes that airlines are permitted to serve.1
* Capacity Control: They establish principles governing the capacity of services, calculated by multiplying flight frequency by the carrying capacity of the aircraft.1
* Economic Regulation: They set procedures for government approval of fares and tariffs, often requiring airlines to consult through organizations like the International Air Transport Association (IATA).1

By using bilateral agreements, states maintain control over their aviation markets while exchanging the "freedoms of the air" necessary for international commercial transport.1