Rescue teams have resumed their search for record-breaking US adventurer and pilot Steve Fossett, who has gone missing in the Nevada desert.
Mr Fossett has cheated death a number of times
The 63-year-old was last seen taking off from a private airfield at the Flying M Ranch near Yerington, Nevada, on Monday evening.
Mr Fossett was flying a single-engine Citabria plane.
Rescuers have since flown more than a dozen sorties, but they say it is like looking for a needle in a haystack.
The search is focusing on an area of 600 sq miles (1,555 sq km), but the only clue as to his whereabouts is that he was intending to fly south.
Mr Fossett's family reported him missing after he failed to return from a trip which should have lasted just a few hours.
Friends of the adventurer, and those searching for him, sounded upbeat on his chances of survival.
Maj Cynthia Ryan of the Civil Air Patrol, the organisation heading the search, said Mr Fossett had a "wonderful history" of surviving on his own.
"He's done it more than once. If anyone has to be lost out there, this guy has the skills to survive."
Sir Richard Branson, a former crewmate of Mr Fossett, said he was confident his friend would be found safe and well.
"Steve is a tough old boot. I suspect he is waiting by his plane right now for someone to pick him up," he told the BBC.
The BBC's David Willis, in Nevada, says the area being combed by search-and-rescue teams is an inhospitable landscape of desert and ravines.
SOME OF FOSSETT'S RECORDS
1998/2002: Long-distance for solo ballooning
2001/2002: Duration for solo ballooning
2002: First solo round-the-world balloon flight
First balloon crossings of Asia, Africa, Europe, South America, South Atlantic, South Pacific, Indian Oceans
Seven fastest speed sailing titles
13 World Sailing Speed Record Council titles
2001: Fastest transatlantic sailing
2004: Fastest round-the-world sailing
Round-the-world titles for medium airplanes
US trans-continental titles for non-military aircraft
High winds have hampered the search effort, making it difficult for planes to fly low enough to peer into the gullies.
But Mr Fossett had plenty of fuel, along with a radio and mobile phone - so the longer his silence continues, the more ominous it becomes, our correspondent says.
Mr Fossett made his fortune in the American financial services industry.
But he is best known for the impressive number of world records he has broken as a pilot, balloonist and sailor.
He has set 116 records in five different sports, more than 60 of which remain unbroken.
Last year Mr Fossett broke the world record for flying further than anyone else in history.
In March 2005, he became the first person to fly a plane solo around the world without refuelling.
And in 2002 he was the first person to fly a balloon around the world solo.