Just when you thought maybe you were balling big time, Microsoft billionaire Paul Allen shut down the game. He just rolled out the world’s biggest airplane, but it won’t be used for passengers or traveling around the world like a king.

Allen created Stratolaunch in 2011 to fling satellites into orbit using an Orbital ATK Pegasus XL rocket carried high up by the world’s biggest airplane instead of starting at sea level, letting it start high above most of the atmosphere. Orbital already launches Pegasus XL rockets using a converted Lockheed L-1011 TriStar jumbo jet, but Stratolaunch will be able to carry three of the rockets for launch on each flight.

This bad boy stretches 385 feet from wingtip to wingtip and is 238 feet long. It has 28 wheels and power comes from six Pratt & Whitney PW4056 jet engines—the kind that the Boeing 747 jumbo jet uses, but that plane only has four of them.

The combination of massive jet thrust and a huge wingspan let the Stratolaunch plane lift a mind-boggling half-million pounds of payload, which is good considering it has to carry three rockets.

This monster hasn’t yet taken wing. First, the world’s new largest plane actually has to get off the ground. Stratolaunch is performing fueling tests now, filling each of the six tanks separately to check for leaks. Next will come engine runs, taxi tests on the ground, and then ultimately a brave flight crew will take to the skies for the first time. Initially, flights will be under an experimental certification from the FAA.

Stratolaunch says safety is a priority so it’ll take things as slowly as necessary, but it believes a first launch demonstration should be possible in 2019.