Testing follows with a record attempt possibly in April Enlarge Image

Virgin GlobalFlyer will be piloted by Fossett - Branson's partner in previous global balloon attempts, and will fly a total of 40,000 km (25,000 miles).

The plane was designed by Burt Rutan, designer of Voyager, a two-man aircraft that completed the challenge in 1986.

The launch date is not yet set, but will either be in April or October.

When the attempt begins will depend on the jet stream winds, which have to be sufficiently strong to carry the exceptionally light aircraft. It is hoped the attempt will take just under 80 hours to complete.

Sir Richard Branson, chairman of Virgin Atlantic, told the Associated Press: "There aren't many great aviation records left to be had. This is perhaps - apart from space - the last great aviation record for Earth."

Big responsibility

Steve Fossett added: "In aviation, solo flights carry quite a distinction from co-piloted flights, they become more of an endurance endeavour, and become focused on the ability and the performance of a single person.

There aren't many great aviation records left to be had. This is perhaps - apart from space - the last great aviation record for Earth Sir Richard Branson

"I will be totally responsible for flying the airplane at all times, so I carry one level more of responsibility. But that is not the only distinction. My flight is at a different technology level as well. It's a jet flight and it's also a much faster flight."

Mr Branson, who completed the first hot-air balloon crossing of the Atlantic in 1987, will act as the backup pilot for Fossett.

The jet has a 34.5-metre (114-feet) wingspan and is constructed from advanced composite materials which will allow it to carry more than four times its own weight in fuel.

It is powered by a single turbofan Williams FJ44-3 ATW jet engine, which sits above the one-seater, pressurised cockpit.

Flight risks

The aircraft, which is built by Burt Rutan's aerospace firm Scaled Composites, will fly at an altitude of 14 km (45,000 ft) and travel at speeds exceeding 250 knots (440 km/h, 285 mph).

The plane will weigh a little under 10,000 kg (22,000 lbs) when it gets airborne.

The engine sits behind and above the cockpit

GlobalFlyer will burn about 8,000 kg (18,000 lbs) in fuel on its journey, ending up at a weight of less than 1,800 kg (4,000 lbs).

"I am truly impressed, almost beyond words, looking at this amazing and beautiful airplane," said Fossett. "Burt Rutan's team at Scaled have turned a dream into engineering reality."

The flight will originate from somewhere in the central US so the plane is over land while it gains altitude and to ensure that it will be over land at the end of the flight, when it risks running out of fuel.

According to Fossett and Branson, the next steps in the attempt to achieve the first great aviation feat of the 21st Century include flight testing by Scaled Composites test pilots, selecting a launch airport with a 3,680-metre-long (12,000 ft) runway, fine tuning the route and establishing a mission control site.

Global tour

The greatest moment of risk in this venture may come at take-off, when the craft attempts to get airborne fully laden with fuel.

When Voyager made its successful circumnavigation, its wings were bending so much under the weight of fuel it was not clear it would get down the runway at all. Fuel pump problems in flight also nearly saw Voyager ditch in the Pacific.

Scaled Composites is at the forefront of novel aircraft design

GlobalFlyer's route should take it across the Atlantic to the UK. From there the aircraft will go south to the Mediterranean and then route through the Gulf to Pakistan, India, China and Japan.

It will then cross the Pacific and head back to the launch destination. It is likely to fly over or near the following destinations: Montreal, Gander, London, Paris, Rome, Cairo, Bahrain, Karachi, Calcutta, Shanghai, Tokyo, Honolulu, Los Angeles.

Steve Fossett is well known for his record-breaking adventures in balloons, sailboats, gliders and powered aircraft. He is perhaps best remembered for his quest to become the first person to achieve a solo balloon flight around the world - finally succeeding on his 6th attempt in 2002.

Although Virgin Atlantic is sponsoring the flight, the cost of the attempt has not been disclosed.

As with all aviation record attempts, the whole effort will be overseen by the Federation Aeronautique Internationale (FAI).