The 323d Air Division is an inactive United States Air Force unit. Its last assignment was with the Western Transport Air Force at Travis Air Force Base, California, where it was inactivated on 8 May 1960. The wing was initially active as the Boston Air Defense Wing, an air defense organization during World War II. In 1944, when the perception of a possible air attack on the United States diminished, it was stripped of its personnel. After a short hiatus, it became the 323d Combat Crew Training Wing and trained heavy bomber aircrews until the end of the war.