Aviator Steve Fossett is crossing the Indian Ocean in his GlobalFlyer plane after a "scary" take-off in his bid to make the longest non-stop flight.
Steve Fossett says he is now settling into the flight
Fossett said he had to use most of the runway to get off the ground and, to make matters worse, was hit by two birds as his plane took flight.
His journey will carry him around the world once and across the Atlantic twice, landing in Kent, UK.
In total, Mr Fossett hopes to cover a record 41,978km (26,084 miles).
He will aim to break the non-stop distance record set in 1986 by Dick Rutan and Jeana Yeager in a nine-day flight.
Overnight, Virgin GlobalFlyer flew over North Africa at 630km/h (390mph; 340 knots) over Algeria, before crossing Saudi Arabia where at 0830 GMT it was flying at 326 knots at 14,102m (46,266ft).
The journey began on Wednesday when Fossett took off in Florida one day later than scheduled. On Tuesday, the three-day non-stop trip around the world was postponed because of a fuel leak and high winds.
Three hours over the North Atlantic Ocean, Fossett said in a telephone call that his takeoff was "particularly hairy".
"Takeoff was a bit scary, to say the least," he said. "I had to use most of the runway to get off the ground... I couldn't have aborted even if I had wanted to. To make matters worse, two birds hit the aircraft on takeoff."
Hot and cold
Fossett said the difficult ascent pushed temperatures in the aircraft to 54C (130F), knocking out the plane's instruments.
But later, the cabin cooled down, and Fossett said he was "settling in to enjoy the view."
Last March, he landed in Kansas after flying around the globe solo for 67 hours, two minutes and 38 seconds, without stopping or refuelling in a trip spanning 36,989km (22,927 miles).
His newest adventure would take him 1,126km (700 miles) further than the 1999 around-the-world balloon trip by Brian Jones, a Briton, and his Swiss partner Bertrand Piccard on the Breitling Orbiter III.
If everything goes according to plan, Fossett will also beat the distance record set by Dick Rutan and Jeana Yeager in their nine-day, non-stop trip around the world without refuelling aboard the Voyager aircraft in 1986. That trip logged a total of 40,212km (24,987 miles).