Adventurer Steve Fossett, flying a lightweight experimental airplane, circumnavigated the world and was continuing over the Atlantic Saturday on the last leg of his quest to break aviation's distance record.

Fossett was expected to decide early in the day whether to try to finish his nearly 27,000-mile trip and land outside London or to abort. Once over the ocean, there would be little opportunity to land the plane if he ran out of fuel.

"We're coming up to a point in the flight where we're going to have to do some critical calculations on fuel," Kevin Stass, director of mission control in Crawley, England, told AP Radio.

Fossett altered his projected route over the Atlantic Ocean on Friday to make up for lost fuel and weak winds. He had planned to fly the Virgin Atlantic Global Flyer on a northeasterly path across the Atlantic that would allow Newfoundland to serve as an emergency landing site.

But the adjusted path called for Fossett to cross Florida, where he had begun his nonstop journey Wednesday, and take a more southerly path on the flight's last leg to take advantage of better winds. He planned to land Saturday in Kent, England.

"The guys at mission control are looking at every available jet stream to pick the best speed across the Atlantic possible," Fossett said.

Winds were expected to be weak across the Atlantic, and Fossett lost about 750 pounds of fuel because of a leak during takeoff from the Kennedy Space Center, leaving no margin for error.

Fossett entered North American airspace Friday over Mexico's Baja peninsula and soared over New Mexico and Texas, reaching 51,000 feet.

The voyage would break the airplane distance record of 24,987 miles set in 1986 by the lightweight Voyager aircraft piloted by Dick Rutan and Jeana Yeager, as well as the balloon record of 25,361 miles set by Brian Jones and Bertrand Piccard in 1999.