The North American B-1 was a swing-wing bomber intended for high-speed, low-altitude penetration missions. By the end of 1977, three B-1As had made 118 flights totaling 646 hours of flying time, with more than 21 hours at supersonic speeds. Production was canceled June 30, 1977. However, in 1982, the Air Force ordered 100 B-1Bs. The first was delivered June 29, 1985. Currently, the B-1B holds 36 world records in speed, range, and payload capacity. Its operating altitude is 60,000 feet, and it has a range of 7,455 miles.