The 42d Air Refueling Squadron is an inactive United States Air Force unit. It was last assigned to the 42d Bombardment Wing at Loring Air Force Base, Maine, where it was inactivated on 30 April 1994. The squadron's earliest predecessor was the 542d Bombardment Squadron, which served as a heavy bomber training unit during World War II and was inactivated in a general reorganization of Army Air Forces training units in 1944.