The military aircraft that should win the award for looking the most advanced and secretive is perhaps the F-117 Nighthawk, a type designed and built by Lockheed. This stealthy and lethal-looking twin-engine aircraft was designed for ground-attack missions. The F-117 began US Air Force (USAF) operations in 1983 although its existence wasn#t revealed officially to the world until 1988. Despite the #F# in its nomenclature, this was a genuine ground-attack aircraft rather than a fighter, and 64 examples were built. Its design limited it to subsonic speeds, but it could carry a 5,000lb payload of bombs in its internal bay.