From Nevada, the BBC's David Willis reports on the difficult task of finding a lone flier in a vast desert.

Steve Fossett had sufficient fuel for about four to five hours of flying.

Mr Fossett has set 116 records in five different sports

But he didn't file a flight plan, something that is apparently not unusual for a quick fly-around.

What it does mean, though, is that authorities trying to find him now face a real headache.

They have sent up several rescue planes to fly over the very rugged terrain south of Reno, where Mr Fossett was thought to be headed.

But so far there has been no sight of him.

We do know that he apparently was not wearing a parachute when he took off.

Mr Fossett was inducted into America's National Aviation Hall of Fame just a couple of months ago.

This is a man who has broken more than 100 records in several sports, many of which still stand.

In two months he was intending to travel to Argentina to try and set another record, this time in gliding.