Enlarge Image Stratolaunch

Microsoft co-founder Paul Allen didn't live long enough to see the Stratolaunch, an absolute hulk of an aircraft, go on its maiden flight. He died in late 2018, and Stratolaunch took wing on Saturday.

Now playing: Watch this: Watch the Stratolaunch take its first flight!

In a release, Stratolaunch announced the historic milestone, which started off at the Mojave Air and Space Port in California. The massive plane cruised for 2.5 hours over the desert, reaching altitudes up to 17,000 feet (5,200 meters) with a max speed of 189 mph (304 km/h).

A short video shows the takeoff and a snippet of the flight.

Today the #Stratolaunch aircraft flew for 2.5 hours over the Mojave Desert, reaching a top speed of 189 mph. Check out the historic flight here: #StratoFirstFlight pic.twitter.com/x29KifphNz — Stratolaunch (@Stratolaunch) April 13, 2019

Stratolaunch calls the plane "the world's largest all-composite aircraft." It isn't just big to be big. It's designed to use its belly to cradle other vehicles, which can then be launched to space.

If you were to set Stratolaunch on an American football field, its wings would reach across each end zone.

So go ahead an imagine this behemoth taking off and then releasing a rocket from underneath it to ferry a satellite into orbit. The reinforced center wing, which spans 385 feet (117 meters) can hold multiple launch vehicles weighing 500,000 pounds (226,796 kilograms).

The pilots checked off an extensive to-do list that included performing flight-control maneuvers and simulated landing approach exercises. The airplane returned safely to the ground after the journey.

Allen founded Stratolaunch in 2011 with a vision for "airline-style access to space" as an alternative to ground-based space launch systems.

"We all know Paul would have been proud to witness today's historic achievement," said Jody Allen, chair of Vulcan Inc. and Trustee of the Paul G. Allen Trust.