They are among the most recognizable aircraft in the world: U-2, SR-71 Blackbird, B-2 stealth bomber and F-117 stealth fighter. But in the beginning, few outside the cloistered world of their development knew of their existence. There were rumors of strange black shapes in the skies over Area 51 in Nevada's desert. But not even the families of those who designed, built and flew these top-secret machines knew what was really taking shape. Now, many of the tales of those "black world" airplanes can be told. Six pilots from those programs shared their stories recently at the Society of Experimental...