The Republic F-105 Thunderchief was an American supersonic fighter-bomber used by the United States Air Force. Capable of Mach 2, it conducted the majority of strike bombing missions during the early years of the Vietnam War; it was the only American aircraft to have been removed from combat due to high loss rates.[​1] It was originally designed as a single-seat, nuclear-attack aircraft; a two-seat Wild Weasel version was later developed for the specialized Suppression of Enemy Air Defenses (SEAD) role against surface-to-air missile sites. The F-105 was commonly known as the "Thud" by its crews.