On April 13, 2019, Stratolaunch successfully completed the first flight of the world's largest all-composite aircraft.
The plane has a dual fuselage design and its wingspan is greater than the length of an American football field.
It landed safely back at the Mojave Air and Space Port as a crowd of hundreds of people cheered.
Jean Floyd, the chief executive of Stratolaunch, said: "It was an emotional moment to personally watch this majestic bird take flight. without a doubt, he [Allen] would have been proud".
The plane, built by Stratolaunch Systems Corp, stayed aloft for more than two hours, hitting a top speed of 304km per hour, and reached an altitude of 5 182m.
The mobile launch platform aims to enable airline-style access to space as its centre wing can support multiple launch vehicles, weighing up to a total of 500,000 pounds.
Stratolaunch was established in 2011 by Microsoft cofounder Paul Allen, who died in October previous year.
The Stratolaunch aircraft is created to act as a flying launch pad for satellites and put payloads in orbit.
Stratolaunch has said that it intends to launch its first rockets from the Roc in 2020 at the earliest. "The aircraft is a remarkable engineering achievement and we congratulate everyone involved".