The dual-fuselage plane has a wingspan of 385 feet and is now the largest aircraft by wingspan to ever take to the skies. With this successful first test flight though, it proves that their plane concept does work and could see an increasing amount of interest from other aerospace companies looking to release rockets into space.
The Mojave Air & Space Port is located in California (the "Golden State") and is the first site which is licensed to horizontally launch reusable spacecraft from.
He added: "Today's flight furthers our mission to provide a flexible alternative to ground launched systems".
The world's biggest airplane took flight on Saturday.
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Moreover, it conducted simulated landing approach exercises at a max altitude of 15,000 feet mean sea level.
Stratolaunch is created to function as a launch platform for rockets delivering payloads to space.
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. While it does have the largest wingspan, it does not have the longest nose-to-tail length.
"We all know Paul would have been proud to witness today's historic achievement", said Jody Allen, Paul's sister and chairwoman of Vulcan Inc., one of Paul Allen's companies. "The aircraft is a remarkable engineering achievement and we congratulate everyone involved".
This enormous aircraft took flight on Saturday.