A brief history of stealth aircraft

Just a generation ago, it was a hush-hush military project, a futuristic aircraft that fit right into the shadowy cloak-and-dagger atmosphere of the Cold War. Nowadays the F-117A Nighthawk stealth aircraft--the first of its kind--is making a high-profile circuit of the world's air shows, from New Mexico to Dubai, as it heads into retirement.

But even today, the plane is still as startling a sight as it was in the late 1980s when the Pentagon first revealed it to the public, all triangles and trapezoids. Those long edges and slopes, along with smaller serrations spread across the airframe, are key elements of how the F-117A hides in plain sight--they scatter and redirect radar signals away from the radar detector that sent them skyward.

Stealth design has taken a more streamlined turn in subsequent aircraft, from the B-2 Spirit bomber to the F-22 Raptor that the Air Force has designated as the Nighthawk's successor.