Developed in the 1960s by General Dynamics, the F-111 pioneered variable-sweep wings, afterburning turbofan engines, and automated terrain-following radar for[-]low-level, high-speed flight. Its design influenced later variable-sweep wing aircraft, and some of its advanced features have become commonplace. Being relatively[-]expensive to maintain amid post-Cold War budget cuts, the USAF elected to retire its F-111 fleet during the 1990s.