Steve Fossett made a fortune as a commodities broker in Chicago before embarking on a second career as an adventurer and record setter. He vanished while piloting an aircraft over the Nevada desert. He took off from Yerington, Nevada, on September 3, 2007, on what should have been a three-hour flight. But despite a huge search neither he nor his aircraft was seen again.

Fossett had already amassed a formidable list of sporting achievements when, in 1992, at the age of 48, he turned to breaking records with a will, chiefly at sea and in the air. In little more than 14 years he set a total of 116 world records. Among the most notable were the transatlantic west-to-east and the round-the-world non-stop sailing records; the first non-stop round-the-world solo balloon flight; and, perhaps most remarkable of all, in 2005 the first non-stop round-the-world solo aircraft flight.

Among this cascade of records, Fossett also set 11 gliding world records; completed the 1,160 miles of the Iditarod sled race in Alaska; twice drove in the Le Mans 24-hour race; drove the Dayton 24-hour race and the Paris-Dakar rally; competed in the Ironman triathlon in Hawaii; and climbed all 54 peaks in Colorado over 14,000ft (he estimated that in total he had climbed 350 mountains). Earlier, in 1985, the same year that he climbed the highest mountain in Antarctica, the Vinson Massif, he swam the English Channel.

His business career was scarcely less remarkable. He made his first million by 1977, when he was 33. By the mid-1980s, he was making upwards of $10 million a year. By his own estimate, after just four years in the business he had become one of the seven most influential commodity brokers in the world.

His business philosophy mirrored exactly his approach to breaking records: to study every challenge from every angle and then, as sure as you could be that you had mastered it, to risk everything. Risk provided the stimulus on the trading floor just as much as it did at sea or in the air - but only when he was dictating terms.

There was little remarkable about Fossett personally. He was modest to a fault, his home life a model of Middle American probity. He had no very obvious athletic talents beyond endurance. When he swam the Channel, his time of 22hr 15min was not just the slowest of the year, it was slower than that of Matthew Webb in 1875, the first man to complete the swim. During his 67-hour, solo round-the-world flight in 2005, he never slept for more than five minutes at a time.

James Stephen Fossett was born in Tennessee and brought up mostly in southern California. The focus of his childhood and adolescence was the Boy Scouts, which he joined on the earliest date he could, his 11th birthday. Within three years he had risen to Eagle Scout, the highest rank in the movement. The values they instilled in him, of discipline and self-reliance, never left him. As important, they introduced him to an outdoor life that he relished instantly.

This taste for adventure was underlined in 1965, with Fossett now at Stanford University, where he majored in economics. That summer he travelled to Europe, determined to swim the Hellespont and the Bosphorus. Not only did he do so, he then climbed Mount Olympus, the Eiger, Mont Blanc and the Matterhorn.

He graduated from Stanford in 1966 and spent two years, during which he gained his pilot's licence and got married, studying for an MBA at Washington University in St Louis. He subsequently worked for IBM in New York and Touche-Ross in Detroit before moving to Chicago to join Merrill Lynch and later Drexel Burnham as a commodities broker. Success was almost instant. In 1981 Fossett opened his own brokerage firm.

Though a ferociously hard worker, Fossett was now able to take time off when he wanted. Six weeks a year were devoted to a series of increasingly gruelling activities. The first goals were the seven highest mountains on each continent and the English Channel. The former defeated him. In 1992, on his second visit to Everest, he realised that a lung problem, contracted in childhood, had put the mountain beyond his reach. The Channel, too, seemed likely to prove too much. It was only on his fourth attempt that he swam it.

Throughout the 1970s he raced cars. In 1978 and 1979 he also competed in the World Loppett League, crosscountry ski races in nine countries. In 1983 he rode in the 762-mile Paris-Brest-Paris bicycle race.

With retirement in 1992, he flung himself into more such activities, determined to be first or to go faster, record-breaking unashamedly the goal. Though he had no experience in either sport, he settled first for sailing and ballooning, his immediate goals to sail the Atlantic single-handed and to make the first round-the-world balloon flight.

The sailing records that followed, first on the 60ft trimaran Lakota, from 1999 on 125ft PlayStation (later renamed Cheyenne), were astounding. They included the east-to-west Pacific record (in 1996, the same year that Fossett set a record solo time across the Pacific); the west-to-east and east-to-west Atlantic records (in 2001 and 2002 respectively); and record times round the Isle of Wight (in 2001), Britain and Ireland (in 2002) and for the Fastnet race (also in 2002). None, however, counted for more than the round-the-world record of 58 days and 9 hours set by Cheyenne in 2004, a time almost six days inside the existing record.

Over the same period, Fossett made no fewer than six attempts to fly non-stop round the world in a balloon. In the end, Bernard Piccard and Brian Jones stole line honours, making the flight in 1999. But Fossett was the first to do so solo, in an epic flight in 2002 that lasted 13 days 8 hours and covered 20,262 miles. In 1995 Fossett had also become the first man to fly a balloon solo across the Pacific. He also turned to gliding. Between 2002 and 2007, flying with the New Zealander Terry Delore, he set 11 world records, including the world's longest flight of 1,370 miles, made in Argentina in 2004. In 2006, with the former Nasa test pilot Einar Enevoldson, he set a world altitude gliding record of 50,671ft.

His non-stop solo round-the-world aircraft flight in 2005 may have owed much to the design genius Burt Rutan, the man behind Fossett's extraordinary machine, the Virgin Atlantic GlobalFlyer. But it could never have happened without Fossett's particular brand of single-minded determination. In the event, Fossett made not just one but two solo round-the-world non-stop flights in the GlobalFlyer, in 2006 bettering his own distance record for any aircraft, set on his first flight, by flying 25,766 miles in 76hr 42min.

No sooner was one challenge overcome than Fossett launched himself on another: an attempt on the world land-speed record of 763mph set in 1997 by the Briton Andy Green. Preliminary testing was due to begin only a matter of weeks after he disappeared.

He is survived by his wife, Peggy. There were no children.

Steve Fossett, businessman and adventurer, was born on April 22, 1944. He was declared dead by a Chicago court on February 15, having disappeared on September 3, 2007, aged 63