Pentagon developing supersonic shape-shifting assassin

For years, the U.S. military has wanted a plane that could loiter just outside enemy territory for more than a dozen hours and, on command, hurtle toward a target faster than the speed of sound. And then level it.

But aircraft that excel at subsonic flight are inefficient at Mach speeds, and vice versa. The answer is Switchblade, an unmanned, shape-changing plane concept under development by Northrop Grumman.

When completed (target date: 2020), it will cruise with its 200-foot-long wing perpendicular to its engines like a normal airplane. But just before the craft breaks the sound barrier, its single wing will swivel around 60 degrees (hence the name) so that one end points forward and the other back.