Microsoft co-founder Paul G. Allen announced Tuesday that he and aerospace engineer Burt Rutan are building the largest aircraft that will be able to launch a satellite or spacecraft into orbit.

Allen said in a press conference in Seattle that his newly formed company Stratolaunch Systems will build the revolutionary aircraft that will have a wingspan of 117 metres (385 feet), six 747 jet engines and a payload capacity of more than half a million kilograms (1.2 million pounds).

The plane's wingspan is longer than a football field and will exceed the existing longest wingspan, 97 metres (319 feet), belonging to the Hughes H-4 Hercules or Spruce Goose.

The aircraft has two fuselages with a booster rocket carrying the payload in between. It will take off like an ordinary airliner from a 3,657-metre (12,000-foot) runway and fly up to an altitude of 2,407 kilometres (1,300 nautical miles), where it will launch the payload into orbit.

The company plans to launch its first flight with an unmanned payload by 2016. Later, it will launch manned spacecraft into orbit.

The carrier aircraft will be developed by Scaled Composites, the aircraft manufacturer and assembler founded by Rutan. A multi-stage booster will be manufactured by the Space Exploration Technologies, a company of PayPal founder Elon Musk. Dynetics, a leader in the field of aerospace engineering, will provide the engineering system that will allow the carrier aircraft to carry the booster, which weighs up to 222,260 kilograms or nearly half a million pounds.

"We are at the dawn of radical change in the space launch industry. Stratolaunch Systems is pioneering an innovative solution that will revolutionize space travel," said Allen.

Rutan said, "Paul and I pioneered private space travel with SpaceShipOne, which led to Virgin Galactic's commercial suborbital SpaceShipTwo Program. Now, we will have the opportunity to extend that capability to orbit and beyond."

Stratolaunch Systems CEO and President Gary Wentz, a former chief engineer at NASA, said the system's design will revolutionize space travel.

Former NASA Administrator Mike Griffin, also a Stratolaunch board member, said, "We believe this technology has the potential to someday make spaceflight routine by removing many of the constraints associated with ground-launched rockets," Griffin said. "Our system will also provide the flexibility to launch from a large variety of locations."

The Stratolaunch aircraft will have a wingspan longer than a football field.