MINDEN, Nev. (AP) - Pilots brushed off a series of false sightings and scoured Nevada's high desert Saturday as the massive aerial search for Steve Fossett grew more urgent nearly a week after the adventurer's disappearance.
Maj. Cynthia Ryan of the Nevada Civil Air Patrol said the search could continue for weeks. But concerns about the 63-year-old aviator's ability to survive in the harsh landscape were growing, and there were no solid clues about where his plane might have gone down.
The search included 45 airplanes and helicopters - 25 under the jurisdiction of the civil air patrol and the rest flown by private pilots operating from a ranch owned by hotel mogul Barron Hilton, about 80 miles southeast of Reno.
"It's the biggest one I've ever been involved in," Ryan said of the search.
Authorities believe Fossett was carrying just a single bottle of water when he took off from the private airstrip on Hilton's ranch Monday morning for a three-hour flight.
"There's been nothing, absolutely nothing," said John Kugler of Nebraska, a close friend of Fossett's who taught him ballooning. "Nobody knows anything. It's a mystery."
Fossett, who made millions as a commodities broker in Chicago, is the first person to circle the globe solo in a balloon. He also swam the English channel, completed the Iditarod Sled Dog Race, sailed around the world and scaled some of the highest mountains on Earth.
When his plane disappeared, Fossett was believed to be scouting dry lake beds as possible locations for his latest thrill ride, an upcoming attempt to break the land speed record in a rocket-propelled car.
Associates say he is not only a top aviator but also a first-rate survivalist.
Still, Saturday marked the sixth day he has been lost in one of the most unforgiving regions in the continental United States. Authorities expanded the overall size of the search area from 10,000 square miles to 17,000, a region about twice the size of New Jersey.
In a stark illustration of the region's remoteness, searchers have discovered six old plane crashes that had not previously been identified since they began the intensive hunt for Fossett on Tuesday.
Crews are marking crash sites discovered during the Fossett search and will return later to examine them in detail. No human remains have been found, which is no surprise in a region where coyotes and mountain lions are prevalent.
Pilots from Hilton's Flying M Ranch have joined the hunt for Fossett throughout the week, help welcomed by the authorities conducting the official search. The pilots flying from the ranch, which has its own mile-long runway, operate in conjunction with the Nevada Civil Air Patrol. Hilton spokesman Pat Barry said the pilots were friends of Fossett's.
"It's the aviation community," he said. "They're tight-knit."
The Nevada Army and Air National Guard combined have spent about $180,000 so far on the search for Fossett, Nevada Guard spokeswoman April Conway said.
Officials for the Nevada Highway Patrol and Civil Air Patrol said Friday they do not know how much their agencies have spent.
Associated Press Writers Brendan Riley in Carson City and Scott Sonner in Reno contributed to this report.