The Fairchild Republic A-10 Thunderbolt II is a single seat, twin-engine, straight wing jet aircraft developed by Fairchild-Republic for the United States Air Force. Its official name comes from the Republic P-47 Thunderbolt, a fighter particularly effective at close air support. The A-10 is more commonly known by its nicknames “Warthog” or “Hog”. The A-10 was designed for close-in support of ground troops, close air support, providing quick-action support for troops against helicopters, vehicles, and ground troops. It entered service in 1976 and is the only production-built aircraft that has served in the USAF that was designed solely for CAS. Its secondary mission is to provide forward air controller – airborne (FAC-A) support, by directing other aircraft in attacks on ground targets. Aircraft used primarily in this role are designated OA-10.