One of the first ATAs after World War II was the Bermuda Agreement, signed in 1946 by Britain and the United States. The features of this agreement have become models for the thousands of such agreements that were to follow, although in recent decades some of the traditional clauses of these agreements have been modified (or „liberalized”) in accordance with the „open skies” policy of some governments, particularly the United States.  Air Agreements (SAAs) are formal agreements between countries – accompanying memoranda of understanding (MoU) and diplomatic exchange notes. It is not mandatory to have an ASA for the operation of international services, but cases where there are services without a contract are rare. Each State Party shall grant to other States Parties, in scheduled international scheduled air services, the following freedoms of carriage by air: designate the route to be used in its territory by an international air service and the airports that such a service may use; The bilateral system is based on the Chicago Convention and related multilateral treaties. The Chicago Convention was signed in December 1944 and has regulated international air transport ever since. The Convention also contains a number of annexes covering issues such as aviation security, security oversight, airworthiness, navigation, environmental protection and facilitation (acceleration and departure at airports). Subject to the provisions of the above section, any State Party may conclude agreements concerning international air services which are not inconsistent with this Agreement. Such an agreement shall be immediately registered with the Council, which shall publish it as soon as possible. In 1913, a bilateral exchange of banknotes between Germany and France was signed in the agreement probably as soon as possible in order to allow airship services. The privileges of this Section shall not apply to airports used for military purposes, excluding scheduled international air services. In areas of active hostility or military occupation and in time of war along the supply routes leading to those areas, the exercise of such privileges shall be subject to the authorization of the competent military authorities.
If disputes between two or more States Parties concerning the interpretation or application of this Convention cannot be settled by negotiation, the provisions of Chapter XVIII of this Convention shall apply in the same manner as they are provided for therein with regard to differences in the interpretation or application of this Convention. . . .