Traditionally, an airline needs the approval of the governments of the various countries involved before it can fly in or out of a country or even fly over another country without landing. Before World War II, this did not present too many difficulties since the range of commercial planes was limited, and air transport networks were limited and nationally oriented. In 1944, an International Convention was held in Chicago to establish the framework for all future bilateral and multilateral agreements to use international air spaces. Five freedom rights were designed, but a multilateral agreement went only as far as the first two freedoms (right to overfly and right to make a technical stop). The first five freedoms are regularly exchanged between pairs of countries in Air Service Agreements. The remaining freedoms are becoming more important, however.
Freedoms are not automatically granted to an airline as a right; they are privileges that have to be negotiated and can be the object of political pressures. All freedoms beyond the First and the Second have to be negotiated by bilateral agreements, such as the 1946 agreement between the United States and the UK, which permitted limited “fifth freedom” rights. The 1944 Convention has been extended since then, and there are currently nine different freedoms (see above figure):
- First Freedom. The freedom to overfly a foreign country (A) from a home country en-route to another (B) without landing. Also called transit freedom. With the end of the Cold War, the first freedom is widely available across the world, but countries such as Russia often limit the transit freedom to a few carriers.
- Second Freedom. The freedom to stop in a foreign country for a technical/refueling purpose only. A flight from a home country can land in another country for purposes other than carrying passengers, such as refueling, maintenance, or emergencies. The final destination is a third country. For instance, in the earlier stages of transatlantic flights, a refueling stop was often required in Newfoundland (e.g. Gander) and Ireland. With the extension of the range of airplanes, this is becoming less relevant.
- Third Freedom. The freedom to carry traffic from a home country to another country for the purpose of commercial services.
- Fourth Freedom. The freedom to pick up traffic from another country to a home country for the purpose of commercial services.
The Third and Fourth Freedoms are the basis for direct commercial services, providing the rights to load and unload passengers, mail, and freight in another country. They are commonly reciprocal agreements implying that the two involved countries will open commercial services to their respective carriers simultaneously.
- Fifth Freedom. The freedom to carry traffic between two foreign countries on a flight that either originated in or is destined for the carrier’s home country. It enables airlines to carry passengers from a home country to another intermediate country and then fly on to third-country with the right to pick passengers in the intermediate country. Also referred to as “beyond right”. This freedom is divided into two categories: Intermediate Fifth Freedom Type is the right to carry from the third country to the second country. Beyond Fifth Freedom Type is the right to carries from a second country to a third country.
- Sixth Freedom. The “unofficial” freedom to carry traffic between two foreign countries via the carrier’s home country by combining third and fourth freedoms. Not formally part of the original 1944 convention, it refers to the right to carry passengers between two countries through an airport in the home country. With the hubbing function of most air transport networks, this freedom has become more common, notably in Europe (London, Amsterdam) and the Middle East (Dubai).
- Seventh Freedom. The freedom to base aircraft in a foreign country for use on international services, establishing a de facto foreign hub. Covers the right to operate passenger services between two countries outside the home country.
- Eighth Freedom. The freedom to carry traffic between two domestic points in a foreign country on a flight that either originated in or is destined for the carrier’s home country. Also referred to as “cabotage” privileges. It involves the right to move passengers on a route from a home country to a destination country that uses more than one stop along which passengers may be loaded and unloaded.
- Ninth Freedom. The freedom to carry traffic between two domestic points in a foreign country. Also referred to as “full cabotage” or “open-skies” privileges. It involves the right of a home country to move passengers within another country.
A salient issue remains that air freedoms are independent of trade agreements. Therefore, a free trade agreement could exist between two nations, implying a liberalization of commercial transactions and the opportunity for respective corporations to invest. However, their respective air carriers could still operate under the same commercial restrictions as before the trade agreement.