Delivering a nuclear strike is only the first phase of a mission. Next comes the most important part: hightailing it out of there before the entire area turns to glass. And for crews aboard America's first supersonic bomber, getting the heck out of Dodge was done at twice the speed of sound.
Developed for the US Air Force's Strategic Air Command in the 1960s, the Convair B-58 Hustler was America's first operational Mach 2 jet bomber. It was also one of the first USAF aircraft to employ a true delta wing design, as it lacked a horizontal stabilizer.
The Hustler, as its name implies, was built for high speeds at high altitudes. As such, it was actually about 20 feet shorter with a wingspan only half as wide as the B-47 Stratojet medium bomber it was meant to replace. However, with a quartet of wing-mounted General Electric J79 engines providing a (sonic) booming 81,000Nm of thrust, the B-58 could cruise along at more than 965km/h at heights reaching more than 19,000m with a maximum speed of more than twice that of sound itself. This would theoretically allow the Hustler -- and its precious nuclear-tipped cargo stowed under the fuselage -- to fly higher and faster than an intercepting MiGs the Soviet's could muster.
However it wasn't MiGs that ended the Hustler's service, it was a new generation of highly-accurate Soviet surface-to-air missiles that could not only reach heights in excess of 18,000m, but were also quick enough to catch the speedy jets. This consequently forced the B-58 to fly at lower altitudes (since they were no longer protected by their flight height) which in turn drastically reduced their operational range on account of the thicker atmosphere down there. Of course, America already had a host of medium range, mid-altitude bombers at its disposal at the time, and the B-58 quickly found itself on the outs. By 1970, Secretary of Defense Robert S. McNamara decided to retire the B-58 from active service. However the plane's design innovations were later integrated into more advanced high-speed bombers like the FB-111A. [Wiki - National Air Force Museum]