During the Vietnam War, thousands of U.S. aircraft were lost to antiaircraft artillery (AAA), surface-to-air missiles (SAMs), and fighter interceptors (MiG)s. The great majority of U.S. combat losses in all areas of Southeast Asia were to AAA. The Royal Australian Air Force also flew combat and airlift missions in South Vietnam, as did the Republic of Vietnam. Among fixed-wing aircraft, more F-4 Phantoms were lost than any other type in service with any nation. The United States lost 578 UAVs (554 over Vietnam and 24 over China). North Vietnam lost 150 – 170 aircraft and helicopters.