B-2 Spirit

The B-2 Spirit is an American nuclear-capable stealth strategic bomber built as a flying wing by Northrop, later Northrop Grumman, for the United States Air Force, reaching initial operational capability on January 1, 1997. Its low-observable flying-wing shape is designed to minimize radar, infrared, acoustic and visual signatures so the aircraft can penetrate sophisticated air defenses undetected. Only twenty-one B-2s were ever built, at a total program cost of 44.7 billion dollars, an average of roughly 2.13 billion dollars per aircraft, making it one of the most expensive military aircraft ever produced. During the 1999 Kosovo War, just six B-2s flying round-trip missions of about thirty hours from a single base in Missouri dropped eleven percent of all bombs used by NATO forces in the conflict, despite representing less than 0.2 percent of the total number of sorties flown.