The Fairchild Republic A-10 Thunderbolt II is a single-seat, twin turbofan engine, straight wing jet aircraft developed by Fairchild-Republic for the United States Air Force (USAF). Commonly referred to by the nicknames "Warthog" or "Hog", its official name comes from the Republic P-47 Thunderbolt, a World War II fighter effective at attacking ground targets. The A-10 was designed for close air support (CAS) of friendly ground troops, attacking armored vehicles and tanks, and providing quick-action support against enemy ground forces. 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.
The A-10 was intended to improve on the performance of the A-1 Skyraider and its lesser firepower. The A-10 was designed around the 30 mm GAU-8 Avenger rotary cannon. Its airframe was designed for durability, with measures such as 1,200 pounds (540 kg) of titanium armor to protect the cockpit and aircraft systems, enabling it to absorb a significant amount of damage and continue flying. Its short takeoff and landing capability permits operation from airstrips close to the front lines, and its simple design enables maintenance with minimal facilities. The A-10 served in the Gulf War (Operation Desert Storm), the American intervention against Iraq's invasion of Kuwait, where the A-10 distinguished itself. The A-10 also participated in other conflicts such as Operation Urgent Fury in Grenada, the Balkans, Afghanistan, Iraq, and against ISIL in the Middle East.
The A-10A single-seat variant was the only version produced, though one pre-production airframe was modified into the YA-10B twin-seat prototype to test an all-weather night capable version. In 2005, a program was started to upgrade remaining A-10A aircraft to the A-10C configuration, with modern avionics for use with precision weaponry. The U.S. Air Force had stated the F-35 would replace the A-10 as it entered service, but this remains highly contentious within the Air Force and in political circles. With a variety of upgrades and wing replacements, the A-10's service life may be extended to 2040; the Air Force has no planned retirement date as of June 2017.