The mega jet has a wingspan the length of an American football field and is powered by six engines on a twin fuselage.

The world’s largest aeroplane made its first test flight on Saturday in California.

The mega jet, called Roc, which has a wingspan the length of an American football field and is powered by six engines on a twin fuselage, carried out its maiden voyage over the Mojave Desert shortly before 7am Pacific time (14:00 GMT).

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.

It landed safely back at the Mojave Air and Space Port as a crowd of hundreds of people cheered.

“What a fantastic first flight,” Stratolaunch Chief Executive Officer Jean Floyd said in a statement posted to the company’s website.

“Today’s flight furthers our mission to provide a flexible alternative to ground launched systems,” Floyd said.

“We are incredibly proud of the Stratolaunch team, today’s flight crew, our partners at Northrup Grumman’s Scaled Composites and the Mojave Air and Space Port,” he added.

Built by the late Paul Allen’s company Stratolaunch Systems, the plane made its first test flight over the Mojave Desert on April 13 [Gene Blevins/Reuters]

Stratolaunch was established in 2011 by Microsoft cofounder Paul Allen, who died in October last year. The company aims to make access to orbit more affordable and accessible by launching satellites into space from aircraft, rather than from the ground.

“We all know Paul would have been proud to witness today’s historic achievement. The aircraft is a remarkable engineering achievement and we congratulate everyone involved,” said the late billionaire’s sister Jody Allen, who is also the chair of his philanthropic trust.