Six engines, Mach 3 speed, nuclear capability—the XB-70 Valkyrie was meant to dominate the skies. But it became one of the Cold War’s biggest "what ifs." This is its story. Trump says he'll ...

An incredible image shows Boom Supersonic's XB-1 jet breaking the sound barrier. The Colorado-based company says specialized photography from NASA shows the shock waves as Boom’s supersonic ...