B-2 Spirit stealth bomber of the USAF. Stealth aircraft are designed to avoid detection using a variety of advanced technologies that reduce reflection/emission of radar, infrared, visible light, radio-frequency (RF) spectrum, and audio, collectively known as stealth technology. Development of stealth technology likely began in Germany during World War II. Well-known modern examples of stealth aircraft include the F-117 Nighthawk, the B-2 Spirit, the F-22 Raptor,and the F-35 Lightning II.
F-117A Nighthawks is a single-seat, twin-engine stealth attack aircraft that was developed by Lockheed's secretive Skunk Works division and operated by the USAF. The F-117 was widely publicized for its role in the Gulf War of 1991. Although it was commonly referred to as the "Stealth Fighter", it was a strictly ground-attack aircraft. The Air Force retired the F-117 on 22 April 2008, primarily due to the fielding of the F-22 Raptor.