Lineage. Designated as 4000 Army Air Forces Base Unit (Command), and organized, on 1 Apr 1944. Redesignated as: 4000 Army Air Forces Base Unit (Air Base) on 21 Feb 1945; 4000 Air Force Base Unit on 26 Sep 1947; 2750 Air Force Base on 28 Aug 1948; 2750 Air Base Wing on 5 Oct 1949; 645 Air Base Wing