U.S. Air Force

Air Force, U.S., branch of the Department of Defense responsible for air warfare and defense and military space research. Prior to 1947 it was a branch of the U.S. Army. Air force personnel are organized into different commands. Among those responsible for actual fighting are the Strategic Air Command (SAC), which is the long-range bombardment and reconnaissance force, and the Tactical Air Command (TAC), which supports land and sea forces in action. Other commands are devoted to communications, intelligence, and training.