In the United States Air Force, a Division was an intermediate level of command, subordinate to a Numbered Air Force, controlling one or more Wings. It also controlled squadrons without associated same-function wings, i.e., 17th Defense Systems Evaluation Squadron had no associated wing, but its function was part of the 24th Air Division. It is now considered obsolete.

On 16 September 1947, the United States Army Air Force became the United States Air Force as a separate and equal element of the United States armed forces. Earlier, on 21 March 1946, General Carl A. Spaatz had undertaken a major reorganization of the Army Air Forces that had included the establishment of the Major Command echelon as the first level of command below Headquarters, USAAF.

The World War II commands, which had been subordinate to the Numbered Air Forces, were eliminated in the reorganization of 1946, and the Numbered Air Forces were made components of the major commands at home and overseas.

The new organizational hierarchy thus contained the following levels : squadron, group, wing, air force, command. In 1948, and afterward, the World War II wings were redesignated Divisions, and placed immediately below the numbered air forces in the organizational pyramid. The "Wing" was redefined to be the USAF basic organizational unit which exercised command and control over a "Base", the physical facility that included the airfield and the support units (groups, squadrons) to support the operation of a wing.