Officials in Nevada say an aerial search is under way for American adventurer Steve Fossett after a small plane he was piloting disappeared Monday night.

A spokeswoman for the Civil Air Patrol, an auxiliary of the U.S. Air Force Tuesday said 13 aircraft are searching the rugged terrain of western Nevada, where Fossett took off in a single engine plane early Monday.

She said Fossett was flying south to look for dry lake beds for work he had planned for the future, and was expected to return by noon.

A spokesman for the U.S. Federal Aviation Administration said Fossett did not file a flight plan before he took off from a private airstrip in Nevada, possibly complicating efforts to locate him.

Fossett is well-known for his record-setting adventures in balloons, sailboats, gliders and powered aircraft.

Civil Air Patrol Spokeswoman Major Cynthia Ryan said the weather conditions were "optimal" for Fossett's flight and he had "more than enough fuel" on board.

In 2002, Fossett became the first person to fly around the world alone in a balloon. In 2005, he became the first person to fly an aircraft solo around the world without refueling.

Some information for this report was provided by AFP and AP.