After World War Two, Germany - split into zones occupied by the victorious Allies - was prohibited from operating any air services. But the need for air transport was acute, even after the dramatic Berlin Airlift ended in 1950.
In those early post-war years, the Western Allies - France, Britain, and the U.S. - set up commercial air links to and from West Berlin, linking that city to the rest of West Germany and the world beyond. In April 1954, Pan American Airways formed the Internal German Service (I.G.S.) with a hub in Berlin and a technical base in Frankfurt. The IGS had many hundreds of German employees and a number of U.S. flight crews. Starting with a fleet of DC-4's, the fleet grew: DC-6's replaced the DC-4's by 1956, and by the end of 1966, the IGS operated an all-jet fleet, operating with Boeing 727's. With time these too were replaced with more modern aircraft. With German re-unification in 1989, the role of the IGS became superfluous, and the operation was taken over by the German carrier Lufthansa in 1990.