Paul Allen, who co-founded Microsoft with Bill Gates, unveiled the enormous aircraft in June 2017

Stratolaunch is designed to carry rockets between its two fuselages before they launch into space from air 

The six-engine plane has a wingspan of 385 feet (117m) which is longer than the length of a football field    

It could run supplies to the International Space Station and deliver satellites and experiments into orbit

Firm is developing a family of craft to be launched, including a manned space plane