#C49 marks the 50th anniversary of the United States Air Force as a part of our National Defense System. Originally a part of the Army and known as the U.S. Army Air Corps, the Air Force was made a separate agency under the Defense Department in 1948. The Boeing B-52 Stratofortress was first flown in 1952. It was built to carry nuclear weapons during the Cold War, but dropped only conventional munitions in combat. These jets have been in continuous service for more than 50 years.