Seattle-based Vulcan Aerospace is on the verge of big things—specifically, creating the world’s largest airplane. Plans for the Stratolaunch Carrier Aircraft, a dual-fuselage, 28-wheel behemoth that measures more than 380 feet from wingtip to wingtip (roughly 120 feet wider than the Airbus A380), have been under development since 2011. Earlier this year, Vulcan began construction of the plane at the Mojave Air and Space Port in California.

Spearheaded by Microsoft cofounder Paul Allen, the new airplane will serve as a research tool and launchpad for a variety of spacecraft. One of the most expensive and challenging parts of sending anything into space is getting it off the ground—literally. The Stratolaunch will eliminate that step by taking off like a conventional jet (notably in all sorts of weather), ascending to 30,000 feet, launching its payload, and then landing.

The hope is that by providing less expensive (one trip will require the fuel equivalent of flying a 747 round-trip from Seattle to Los Angeles) and more reliable access to orbit, the Stratolaunch will help foster space research, exploration, and development. Construction is 40 percent complete, and Vulcan hopes to begin test flights in 2016.