Paul Allen’s monstrous Stratolaunch airplane finally rolled out of its hangar in Mojave, Calif., Wednesday, showing off its complete twin-hulled majesty for the first time.

It will now spend many months on ground tests before a first flight. And it’s not expected to be used to launch a rocket into space — a mission that some observers are skeptical will ever make business sense — any sooner than 2019.

Two tugs pulled the 250-ton giant from the hangar where it was built for Allen’s Stratolaunch Systems company by Scaled Composites, the specialty airplane-development firm founded by aviation pioneer Burt Rutan.

Over the past few weeks, mechanics removed the last of the three-story scaffolding that had surrounded the aircraft during construction, leaving the aircraft’s full weight to rest on its 28 wheels for the first time.

Jean Floyd, chief executive at Stratolaunch Systems, said in a statement that the empty airplane, powered by six used 747 engines, weighs approximately 500,000 pounds.

“That may sound heavy,“ Floyd acknowledged. “But remember that the Stratolaunch aircraft is the world’s largest plane by wingspan, measuring 385 feet. By comparison, a National Football League field spans only 360 feet.”