The world's largest aeroplane by wingspan has taken flight for the first time.
Built by Stratolaunch, the company set up by the late Microsoft co-founder Paul Allen in 2011, the aircraft is designed to act as a flying launch pad for satellites.
The idea is to fly the plane to 10 km (6.2 miles) before releasing satellites into orbit.
Its 385 ft (117 m) wingspan is the length of an American football field.
If successful, such a project would be a cheaper way to launch objects into space than rockets fired from the ground.
The twin-fuselage six-engine jet flew up to 15,000 ft (4,572m) and reached speeds of about 170 miles per hour (274 km/h) on its maiden flight.
The pilot Evan Thomas told reporters the experience was "fantastic" and that "for the most part, the airplane flew as predicted".
According to their website, Stratolaunch aims to "make access to orbit as routine as catching a commercial airline flight is today".
British billionaire Richard Branson's company Virgin Galactic has also developed aircraft that launch rockets into orbit from a great height.
Stratolaunch describes its vessel as the "world's largest plane" but there are aircraft which are longer from nose to tail.