 In the Navy Air Combat Fighter (NACF) competition, on 2 May 1975 the Navy selected the YF-17 as the basis for what would become the McDonnell Douglas F/A-18 Hornet.The U.S. Air Force initially ordered 15 "Full-Scale Development" (FSD) aircraft (11 single-seat and four two-seat models) for its flight test program, but was reduced to eight (six F-16A single-seaters and two F-16B two-seaters).The YF-16 design was altered for the production F-16.