Boeing sent the unmanned X-45B Blended Wing Body, or BWB, experimental aircraft into the sky last week at the NASA Dryden Flight Research Center at Edwards Air Force Base for a 31-minute flight that reached an altitude of 7,500 feet.

The flight was announced by Boeing Thursday. It marked what could become a major step forward in aircraft design. The aircraft has a tailless design and wings that blend seamlessly into a wide and flat fuselage. The result is a futuristic flying machine with the classic UFO look.

"We've successfully passed another milestone in our work to explore and validate the structural, aerodynamic and operational efficiencies of the BWB concept," said program manager Bob Liebeck. "We already have begun to compare actual flight-test data with the data generated earlier by our computer models and in the wind tunnel."

Engineers at Boeing Phantom Works see BWB as leading the way to high-flying military aircraft that is virtually silent in flight and very low in its fuel consumption.

The X-48B weighs in at 500 pounds and has a 21-foot wingspan. It is powered by three turbojet engines and will be put through its paces in a series of low-speed flights at around 140 miles per hour.