LOS ANGELES (AFP) - Internet sleuths using satellite imaging software such as Google Earth have joined the hunt for missing adventurer Steve Fossett, officials said Tuesday.

Fossett has not been heard from since September 3, when he failed to return after taking off on a solo flight from a private airstrip 80 miles (130 kilometers) southeast of Reno, Nevada.

An intensive search and rescue operation involving dozens of aircraft has so far found no trace of the world-record-breaking aviator.

Nevada State Police spokesman Chuck Allen told AFP that volunteers were helping scour more than 10,000 square miles (25,900 kilometers) of rugged Nevada terrain via Internet applications.

"We're continuing to get a number of leads from people searching on the Internet with Google/Yahoo!," Nevada State Police spokesman Chuck Allen said. "We're looking at all those leads but we haven't found anything yet."

A parallel Internet search is also being co-ordinated by administrators of Fosset's official website, www.stevefossett.com, using analysis of Amazon.com's Amazon Mechanical Turk.

Allen meanwhile told AFP that a hotline had been established for people to pass on information about possible sightings and said rescuers were still optimistic of finding Fossett.

"The general mood is still very positive. I took a lead last night that I thought that was extremely credible and we're chasing it down today. As yet nothing has transpired."

Meanwhile rescuers have expressed concern about the possibility of participants in an annual air show straying into airspace being patrolled by rescue planes.

More than 150 aircraft are due to participate in the Reno Air Races which get underway Thursday, giving searchers a potential headache.

"We're asking the flying public to give us a wide berth and don't come in and try to assist," said Civil Air Patrol Major Cynthia Ryan, adding that rescuers remained optimistic of finding Fossett.

"It starts to take its toll on our people as well as others watching the search," Ryan said. "We keep hoping today is going to be the day."

Fossett has survived numerous near-misses and harrowing crash landings over the years, including a 29,000-foot (9,000-meter) plummet into the Coral Sea off Australia because of a storm-shredded balloon.

Fossett's single-engine Bellanca aircraft was equipped with an electronic tracking device designed to be triggered in the event of a rough landing, but it has not been activated.

Fossett made the first solo nonstop, non-refueled circumnavigation of the globe in 67 hours in the Virgin Atlantic GlobalFlyer. In 2002, he was the first person to fly solo around the world in a balloon.