Millionaire adventurer Steve Fossett has been declared dead by a Chicago judge five months after his plane disappeared.

The 63-year-old went missing on September 3 after taking off in a single-engined plane from a Nevada airstrip.

His wife had asked for him to be declared legally dead.

The judge heard testimony from Mr Fossett's wife, Peggy, and a family friend, as well as from a search-and-rescue expert, before deciding there was sufficient evidence to declare him dead.

Mr Fossett earned millions of dollars trading futures and options on Chicago exchanges.

Attorneys representing his estate had filed a petition to have him declared legally dead so his assets could be distributed according to his will.

Mr Fossett was a record-setting balloonist, sailor and pilot who completed non-stop flights around the world.

Mrs Fossett's lawyer, Michael LoVallo, said: "It was very sad and at first she hoped and sort-of envisioned him walking down the road the next day with another story to tell.

"But as the days went on, she realised it wasn't going to happen as it had on other occasions when he'd had close calls."

Mr Fossett was on a pleasure flight when he vanished and was not looking for a dry lake bed to use as a surface on which to set the world land speed record, as was initially reported.