Photos of the X-48B

The airplane is the X-48B, an advanced concept, fuel-efficient blended wing body or BWB. It's called a blended wing body because it looks more like a modified triangular-shaped wing than the traditional aircraft, which is a tube and wing with a tail. One advantage Boeing engineers say the concept has over conventional aircraft is that it's about 30 percent more fuel efficient than an airplane of similar size that carries the same payload.

The Air Force has designated the vehicles as the 'X-48B' based on its interest in the design's potential as a multi-role, long-range, high-capacity military aircraft.