Lockheed F-117 Nighthawk

The Lockheed F-117 Nighthawk is a retired American single-seat, subsonic, twin-engined stealth attack aircraft developed by Lockheed's secretive Skunk Works division and operated by the United States Air Force (USAF). It was the first operational aircraft to be designed with stealth technology.

Work on what would become the F-117 began in the 1970s to counter increasingly sophisticated Soviet surface-to-air missiles (SAMs). In 1976, the Defense Advanced Research Projects Agency (DARPA) issued Lockheed a contract to produce the Have Blue technology demonstrator, whose test data validated the concept. On 1 November 1978, Lockheed decided to develop the F-117. Five prototypes were produced, the first of which performed its maiden flight in 1981 at Groom Lake, Nevada. The first production F-117 was delivered in 1982, and initial operating capability was achieved in October 1983. All aircraft were initially based at Tonopah Test Range Airport, Nevada.

The aircraft's faceted shape (made from two-dimensional flat surfaces) heavily contributes to its relatively low radar cross-section of about 0.001 m² (0.0108 sq ft). To minimize its infrared signature, its non-circular tail pipe mixes hot exhaust with cool ambient air and lacks afterburners; it is also restricted to subsonic speeds, as breaking the sound barrier would produce an obvious sonic boom that would increase its acoustic and infrared footprints. While commonly referred to as the "Stealth Fighter", the aircraft was designed and employed as a dedicated attack aircraft; its performance in air combat maneuvering was less than that of most contemporary fighters. The F-117 has integrated digital navigation and attack systems, with targeting via a thermal imaging infrared system and a laser rangefinder/laser designator. It is aerodynamically unstable in all three aircraft principal axes, thus requiring constant flight corrections via a fly-by-wire flight system to maintain controlled flight.

Even in the years after it entered service, the F-117 was a black project. Its existence was denied by USAF officials until 10 November 1988, when the aircraft was first publicly acknowledged. Its first combat mission was flown during the U.S. invasion of Panama in 1989. The last of the 59 production F-117s was delivered on 3 July 1990. The F-117 gained note in the Gulf War of 1991, during which it flew about 1,300 sorties and struck what the US military described as 1,600 high-value targets in Iraq. F-117s also participated in the conflict in Yugoslavia, during which one was shot down by a surface-to-air missile in 1999. It was also active during Operation Enduring Freedom in 2001 and Operation Iraqi Freedom in 2003. The USAF retired the F-117 in 2008, primarily because the F-22 Raptor had entered service, but has kept some aircraft in flying condition for research and development, testing, and training.