The search for millionaire aviator Steve Fossett, who disappeared a month ago in northern Nevada, was suspended again after what the Civil Air Patrol described as one of the largest efforts to locate a missing plane in modern history.

The decision Tuesday came after renewed efforts over the weekend proved unsuccessful. Planes and ground crews scoured a rugged area southeast of where Fossett was last seen taking off Sept. 3 from an airstrip on hotel mogul Barron Hilton's sprawling ranch.

With deer-hunting season opening in many parts of the state, officials said they hope a hunter will come across the single-engine plane that Fossett had borrowed from Hilton for what was supposed to have been a brief flight.

"We've exhausted all our leads at this time," Amy Courter, acting national commander of the Civil Air Patrol, said in a phone interview. "We didn't find anything. We don't have any conclusive information to follow — or to say there was a crash and he didn't survive."

Courter said that while the search has been officially suspended, it will be revived if new, viable tips come in. The search, effectively suspended by the Nevada Civil Air Patrol and the Nevada National Guard two weeks ago, had been renewed after Air Force experts thought they detected Fossett's flight path from radar and satellite images.

In all, the search encompassed a 20,000 square-mile area, involving Civil Air Patrol pilots from Nevada and seven other states, the Nevada National Guard, the Air Force Rescue and Coordination Center, the state Department of Public Safety and ground crews organized by local authorities.

Experts in radar analysis from the Federal Aviation Administration, Air Force, Navy, National Transportation Safety Board and the Civil Air Patrol also were involved, using high-tech methods to try to determine Fossett's flight path.

Fossett, 63, was the first person to circle the globe solo in a balloon. He also swam the English Channel, completed the Iditarod sled-dog race and scaled some of the world's best-known peaks.