(CNN) -- U.S. adventurer Steve Fossett says he has last-minute nerves as he prepares an attempt on the "last great aviation record" by piloting an airplane alone around the world without refueling or stopping.
If the skies remain clear the 60-year-old former investor will take off Monday from Salina, Kansas, in the single-jet-engined Virgin Atlantic GlobalFlyer, loaded with more than four times its own weight in fuel.
Over the 80 hours the challenge is expected to take, Fossett will fly to Europe and the Middle East, over Asia and the Pacific, and back to Kansas.
If he succeeds, he will have broken several records including the longest time flying non-stop without refueling. But if he fails, his life is in serious danger.
The most dangerous part of the attempt is the take-off, due to take place between 3 p.m. and 6 p.m. local time (2100 and 0000 GMT).
GlobalFlyer has never been tested with a full load of fuel and any unexpected turbulence or technical problems could spell disaster.
The project is partly sponsored by Sir Richard Branson's company Virgin and the British entrepreneur is in Kansas to wish his friend and former ballooning colleague well.
At a news conference at mission control in Kansas State University on Sunday, Fossett appeared strained as reporters' questions focused on what might happen if something went wrong.
"I suppose I am a little bit of a nervous person -- perhaps it is justified in this case," he said.
"It will be very scary to take off in a plane this heavy and the consequences of something going wrong...
"There is very little margin for things like turbulence and tail winds."
Originally scheduled to launch on February 2, unsatisfactory weather has prompted mission planners to delay the flight several times.
The GlobalFlyer consists of three hulls attached to a 35-meter (114-foot) wing that measures more than half the wingspan of a Boeing 747. Twin "boom" hulls on either side of the cockpit hull each carry almost 2,500 kilograms (5,500 pounds) of fuel. The plane is expected to reach heights of 17,000 meters (52,000 feet) and travel at speeds in excess of 250 knots (440 kph, 285 mph).
Atop the plane's 7-foot cockpit is a single jet engine, which must propel the aircraft throughout its 15,500 km (25,000-mile) trek.
"The first solo nonstop is a grand endeavor," said Fossett. "If successful, I hope to earn a place in aviation history in the legacy of Wiley Post." In 1933, Post rounded the globe after stopping 11 times in just under eight days.
