Boeing Co. has completed the first test flight of its latest blended-wing-body research aircraft, designated the X-48B, which carries hopes that future planes could be built much bigger than current ones, the U.S. aircraft manufacturer announced Wednesday.

The unmanned test vehicle at a NASA flight research center in California last week represents a possible future aircraft that replaces the traditional tube-and-wing design with a shape a flying wing, the company said.

During the test, the prototype, which has a 6-meter wingspan and weighs over 200 kilograms, flew for a half-hour at Dryden Flight Research Center at Edwards Air Force Base, climbing to an altitude of about 2.2 kilometers.

Thanks to greater aerodynamic efficiency, a blended-wing-body design could be built much bigger than current planes and carry more passengers or cargo.

For commercial applications, a big drawback of such bigger planes is that most passengers in the cavernous interior would be far from windows. And Boeing is first looking at such applications as military cargo.

A Boeing official said at the Paris Air Show last month that, with continued government funding, a blended-wing-body military- cargo plane could be in use sometime between 2015 and 2020.

Meanwhile, Boeing announced Wednesday that the company swung to profit in the second quarter this year thanks to a strong demand for its commercial airplanes, and reaffirmed its target to keep its next-generation 787 jets on schedule.

The world's No. 2 commercial plane maker behind Airbus is on pace to overtake its European rival in deliveries by early next year on momentum from the 787 Dreamliner, which so far has 683 firm orders from nearly four dozen customers.

Boeing said it was working to address issues related to delivery of the massive aircraft, but expect the plane will arrive on time in May 2008. The first 787 rolled out from the assembly line in a Boeing factory in Seattle earlier this month at a high- profile ceremony.