World War II had been over for two years and the Korean War lay three years ahead when the Air Force ended a 40-year association with the U.S. Army to become a separate service. The U.S. Air Force thus entered a new era in which airpower became firmly established as a major element of the nation's defense and one of its chief hopes for deterring war.
The Department of the Air Force was created when President Harry S Truman signed the National Security Act of 1947. It became effective Sept. 18, 1947, when Chief Justice Fred M. Vinson administered the oath of office to the first secretary of the Air Force, W. Stuart Symington, a position filled by presidential appointment.
Air Force Vision
The United States Air Force will be a trusted and reliable joint partner with our sister services known for integrity in all of our activities, including supporting the joint mission first and foremost. We will provide compelling air, space, and cyber capabilities for use by the combatant commanders. We will excel as stewards of all Air Force resources in service to the American people, while providing precise and reliable Global Vigilance, Reach and Power for the nation.
Air Force Mission
The mission of the U. S. Air Force is to fly, fight and win ... in air, space, and cyberspace.
Excerpted from the Air Force’s official web site.