CNN announced Thursday's confirmation. No human remains were found.
"They did locate an aircraft which we have now confirmed is the one Steve Fossett was flying when it disappeared last Labor Day," Madera County, Calif., Sheriff John Anderson said at a press conference.
The news comes after hiker Preston Morrow said that on Monday he found three identification cards bearing Fossett's name and $1,005 cash in a bush just west of the town of Mammoth Lakes.
"It was just weird to find that much money in the backcountry, and the IDs," said Morrow. "My immediate thought was it was a hiker or backpacker's stuff, and a bear got to the stuff and took it away to look for food or whatever."
Morrow's discovery made Fossett's widow, Peggy Fossett, optimistic that closure was a possibility. In a statement Wednesday, she said. "I am grateful to all of those involved in this effort."
Legally DeadAfter searching a 20,000-sq.-mi. area, authorities in February declared Fossett legally dead after investigators concluded that his airplane was destroyed in a fatal accident.
On Sept. 3, 2007, Fossett took off from a private airstrip known as Flying M Ranch, 30 miles south of Yerington, Nev., with enough fuel for four to five hours of flight. By that evening, he was announced as missing.
In 2002, Fossett became the first person to fly solo around the world in a balloon. Three years later, he became the completed the first solo, non-stop, non-refueled airplane trip around the world.
He's credited with 115 world records or world firsts, and holds official world records in five sports, he claimed on his Web site.
Gary Newkirk / Allsport / Getty