In cooperation with NASA and the U.S. Air Force Research Laboratory, the Phantom Works organization of Boeing is taking another step toward exploring and validating the structural, aerodynamic and operational advantages of a futuristic aircraft design called the blended wing body, or BWB. Two high-fidelity, 21-foot wingspan prototypes of the BWB concept have been designed and produced for wind tunnel and flight testing this year. The Air Force has designated the vehicles as the "X-48B," based on its interest in the design's potential as a flexible, long-range, high-capacity military aircraft.