Stansted was constructed by the United States Army in 1942 as a bomber base. By 1944, over 600 aircraft were stationed there. The base played a major role in the Battle of Normandy. After the war, the base was not needed; it was transferred to the Air Ministry in 1947. The US military returned in 1954 to extend the runway for a possible transfer to NATO but this was never realised and the airport ended up under British Airports Authority control in 1966.