The U.S. Air Force has, to put it mildly, a mixed record building strategic bombers over the past 60 years. The B-1 Lancer was poorly regarded from the start, and canceled by Jimmy Carter before being revived by Ronald Reagan following his 1980 election. The B-2 Spirit, known for its stealthy, fuselage-free profile, was so expensive that Congress and George H.W. Bush agreed to cut the fleet to just 20 aircraft. The spotty performance managing bomber programs helps explain why the Air Force keeps about 70 aging B-52s in service, six decades after that production line shut down.