By William Albright RENO, Nevada, Sept 7 (Reuters) - Air crews planned to search a vast area of the Nevada and California desert for a fifth day on Friday in the hope of spotting missing U.S. adventurer Steve Fossett. Two aircraft equipped with infrared technology flew throughout Thursday night looking for the 63-year-old millionaire and aviation record-setter whose plane disappeared on Monday. Fossett had been scouting sites for a planned attempt to set a land speed record. Authorities dramatically expanded the scope of the search area on Thursday to 10,000 square miles (26,000 sq km) -- equivalent to the state of Maryland -- from an original 600 square miles (1,600 sq km). They also added ground patrols of mountainous areas and sent boats to check out Nevada's Walker Lake in addition to the 12 or more planes searching the terrain. Some are equipped with imaging technology that quickly distinguishes man-made objects, including aircraft wreckage, from natural objects. Air and ground searchers have so far come up empty-handed, finding no signs of either Fossett's small single-engine plane, nor any indication of what might have happened to him. Maj. Cynthia Ryan of the Nevada Civil Air Patrol said on Thursday the task was like looking for a needle in a haystack and could take weeks. "Searches of this nature very typically can go on two weeks and longer. So four days into it, we are still scratching the surface," Ryan said. British billionaire Richard Branson, who teamed up with Fossett on several aviation adventures and who underwrote his record-setting solo nonstop airplane flight around the world in 2005, said he had tried to find Fossett using satellite mapping from Internet search company Google Inc. Fossett earned his fortune as a financial trader. In 2002 he became the first person to fly a balloon solo around the world.
