The development of the Lockheed F-117 Nighthawk - the world's first in-service combat aircraft specifically designed to be undetectable by radar - was a huge leap forward in military aviation technology. It was followed by the stealthy F-22 Raptor and F-35 Lightning II; yet for every type that has entered service there have been dozens of secret projects and proposals for stealth fighters which never reached production. In US Stealth Fighter Projects, aerospace engineer Scott Lowther brings to light some of the fascinating might-have-been designs for fighters intended to attack and destroy their opponents before even being detected.