The LTV A-7 Corsair II had been a light assault aircraft in line with the F-8 Crusader. The A-7 had been one of the first combat aircraft to feature a head-up display (HUD). doppler-bounded inertial navigation system, and a turbofan engine. It served with the United States Navy and also the usa Air Force, and later with all the Air National Guard. It was additionally exported to South Vietnam (throughout the Vietnam War), Greece (A-7H), Portugal(A-7P), and Thailand (within the belated 1980s)