The Department of the Air Force was established 78 years ago on Sept. 18, 1947, making it the third military department, alongside the Departments of the Army and Navy.
Its creation was the result of the National Security Act of 1947, which formed the National Military Establishment. Less than two years later, the establishment became the Department of Defense, and on Sept. 5, 2025, President Donald J. Trump signed an executive order renaming DOD as the War Department.
Included in the Department of the Air Force are the Air Force, Space Force, Air Force Reserve, Air National Guard and the Civil Air Patrol. The Air National Guard is the Air Force's component of the National Guard Bureau, along with the Army National Guard.
The Air Force mission is to fly, fight and win — airpower anytime, anywhere. It is achieved by air superiority, global mobility in troop movement and munitions for the joint force and maintaining two legs of the nuclear triad: bombers and intercontinental ballistic missiles.
The Air Force also supports humanitarian and natural disaster missions.
The Air Force was originally a part of the Army beginning in 1908, when the service received its first powered military aircraft from the Wright brothers.
During World War II, the air arm of the Army was known as the Army Air Forces, a designation that lasted until the creation of the Air Force.
The Army was never eager to give up its air branch, particularly for close air support. In the 1950s, the service began taking delivery of helicopters, thereby effectively re-creating an air arm for troop movements and fire support.
The Navy and Marine Corps fared better, as they retained all their fighter and transport aircraft.