Sir Richard Branson says the Burt Rutan designed GlobalFlyer, which is backed by his Virgin Group, will now probably set of early next year.
American adventurer Steve Fossett plans to become the first lone pilot to fly non-stop around the world without refueling.
Rutan was also responsible for designing Voyager, a two seater aircraft that set the record in 1986.
On that trip his brother Dick was one of the pilots, along with Jeana Yeager.
The Rutan’s screened a video of GlobalFlyer’s test flights during their lecture at the Royal Aeronautical Society. The aircraft recently completed an eight-hour test flight.