Richard Branson and Steve Fossett have announced the launch of the first solo-piloted aircraft to fly non-stop round the world without refuelling.
GlobalFlyer, as it is known, will be piloted by Fossett - Branson's partner in his global balloon attempt.
A plane called Voyager, which carried two pilots, completed the challenge for the first time in 1986.
GlobalFlyer, which is due to take off next year, is designed by Burt Rutan, who also created Voyager.
Sleek and slim
The GlobalFlyer, which has not been completed yet, will be a sleek and slim, if slightly odd-looking aircraft. It will be extremely fuel efficient, burning less fuel per kilometre than a Mini Cooper.
The aircraft, code named Model 311, is being constructed in the US Mojave Desert by Scaled Composites. It will be made entirely from advanced materials and will be ultra light.
"GlobalFlyer will be the lightest aircraft relative to fuel weight that has ever been built," said Steve Fossett. "Its shape is designed for high fuel efficiency and low drag."
Having taken off from a central US location, GlobalFlyer will fly at 45,000 feet (13,700 metres) and travel 40,000 kilometres at speeds in excess of 250 knots (285 mph, 440 km/h).
Virgin Atlantic hope the journey will be completed in 80 hours, "as opposed," commented Richard Branson, "to Phileas Fogg's 80 days".
Burt Rutan will draw on his experience as the designer of Voyager to mould the single-engined aircraft specifically for non-stop global circumnavigation.
The Voyager was piloted by Dick Rutan and Jeana Yeager.
It followed a route determined by weather and geography - flying an official distance of 40,211 km (24,986 miles) in 216 hours - 9 days.
One pilot in the cockpit of the Voyager navigated, maintained ground communication and transferred fuel to balance the plane, while the other pilot rested.
Steve Fossett will pilot GlobalFlyer
Steve Fossett will have the extra challenge of doing it all alone.
Fossett and Branson both acknowledge the adventure will be dangerous.
"I have been in training to prepare me mentally and physically for this challenge," said Steve Fossett. "But this is an experimental aircraft and we don't know all the answers yet. It might not stand turbulence, for example, and I may need to bail out."
By "bail out" he means he might have to eject from the plane and parachute down to Earth from a terrifying altitude. "But Steve is used to landing in the Pacific so it's alright," Branson added comfortingly.
The announcement of the GlobalFlyer challenge comes one day ahead of Concorde's last flight.
"It is symbolic that we are announcing this launch the day before Concorde is grounded," said Richard Branson. "We are showing we are interested in the future of aviation. It is a point we are trying to make."
Branson has tried unsuccessfully to persuade the UK Government to let him continue flying Concorde under the Virgin flag for several more years.
"I can't believe tomorrow will be the end of Concorde," continued Branson. "It is a very sad day."
The manufacturers of the GlobalFlyer plane and its engine are using new data, which they say will improve future aircraft efficiency and will help develop a new generation of more economic commercial aircraft.
Burt Rutan's Scaled Composites company is also testing a reusable space plane which many commentators fully expect to win the famous X-Prize.
The $10m prize will go to the team behind the first successful non-governmental manned space mission.