In 1967, the U.S. Air Force initiated the A-X program, designed to field a new generation close air support (CAS) aircraft. This was the first for the air force, which had traditionally used fighters and light bombers (including the A-10’s namesake, the P-47 Thunderbolt) in the CAS role. Although the Air Force’s current stable of fighters, including the famous “100 series” planes favored speed above all else, A-X traded speed for survivability, maneuverability at low speeds, loiter time and, most importantly, lethality. After a flyoff against the Northrop A-9, the Fairchild A-10 was picked and the first jets delivered in 1974.