After being missing for more than a month, the search for aviator Steve Fossett continues. Earlier searches were conducted by plane, that yield numerous unknown crashed planes, but not Fossett. Now, the ground search will consist of teams on ATV vehicles, horseback, and foot.

The ground search, now in its second day, focused on a patch of rugged terrain identified by U.S. Air Force radar analysis as an area where Fossett's aircraft was likely to have gone down, said Gary Derks, a state Department of Public Safety official overseeing the operation.

Speaking to Reuters by telephone from the command center in Nevada's capital, Carson City, Derks said the teams were expected to finish covering the search area of roughly 50 to 60 square miles by nightfall.

Sunday's effort consisted of about 35 searchers on foot, horseback and ATVs, joined by two Nevada Civil Air Patrol planes, Derks said.

A 10 1/2-hour search on Saturday by 50 people on the ground and three Civil Air Patrol aircraft turned up nothing, he said.

Daily aerial searches by the Civil Air Patrol and National Guard were called off after 17 days on September 19, but authorities insisted they had not given up hope and would renew efforts to explore possible crash sites when warranted.

The weekend search concentrated in an area of rugged canyons and dense brush southeast of the ranch in western Nevada where Fossett took off in a single-engine plane, reportedly to scout locations for a planned attempt to set a land-speed record.

The search region was pinpointed by a new Air Force analysis of radar images from September 3 showing a flight "trailing" that they believe was left by Fossett's plane, Derks said.