This is Stratolaunch: world’s largest airplane, with 117-metre wingspan, rolls out of hangar

The initial construction on the massive airplane that billionaire Paul Allen has been quietly building in the California desert is complete.

The world’s largest airplane - assuming it eventually gets off the ground - was wheeled out of its hangar for the first time on Wednesday.

Called Stratolaunch, the plane has some impressive stats: a wingspan of 117 metres, or longer than a football field, a height of 15 metres. Unfueled, it weighs 227 tonnes. But it can carry 113 tonnes of fuel, and its total airborne weight can reach as high as 590 tonnes.

But, really . . .. How big is it? It’s so big that it has 28 wheels and six 747 jet engines. It’s so big that it has 100km of wire coursing through it.

By comparison - the enormous Airbus A380 has a wingspan of 80 metres. The Stratolaunch’s wingspan is about half as big again, making it the world’s largest plane by wingspan; the famous Spruce Goose, built by tycoon Howard Hughes, had a wingspan of 98 metres.

It’s so big that to truly get a sense of it, you have to see it from a distance - like a mountain.

But why is Allen, the co-founder of Microsoft and owner of the Seattle Seahawks, building such a massive plane?