If Steve Fossett had been asked to choose the manner of his parting, it's quite likely he'd have decided to simply fly off into the sunset. And give or take a few daylight hours, that's more or less what happened: on the morning of Monday 3 September 2007, the world-famous adventurer, pioneer and all-round hero of aviation left a secluded Nevada airfield for a routine pleasure flight over the local desert. He never returned.
To fans of the feats of endurance Fossett had shoehorned into his 63 years, the disappearance sparked a mixture of concern – and disbelief. Here was a man who had circumnavigated the globe in a hot-air balloon, and set more than 100 records in five adventure sports (60 of which still stand), and clambered from the wreckage of almost as many crashed aircraft as he'd eaten vacuum-packed dinners. Here, in short, was a born survivor.
Yet here he was, one of the world's most experienced aviators, apparently getting into terminal difficulty during an everyday leisure flight taken in near-perfect conditions, using a small, single-engined aeroplane known for its reliability.
After Fossett's wife, Peggy, raised the alarm, an emergency search of mammoth proportions launched into action. For a month, the Civil Air Patrol, National Guard, and hundreds of flying enthusiasts (most volunteering their aircraft), combed thousands of square miles of mountain, canyon and desert in search of the missing airman.
They searched day and night, logging tens of thousands of flying hours. But, in spite of one of the most thorough and widespread search operations in history, no wreckage, and no body, was ever found. On 15 February this year, Steve Fossett was declared dead by a judge in his home town of Chicago.
That should have been the end of it. But, like any unsolved mystery, the disappearance of Fossett has retained an enduring fascination for his many admirers who have continued (often against his widow's wishes) to search for the adventurer's remains. And, this week, that unsolved mystery took an extraordinary turn.
On Sunday, Lt-Col Cynthia Ryan of the US Civil Air Patrol, official spokeswoman for the search-and-rescue operation, was quoted as saying that she believes Fossett may not have actually crashed. Her astonishing theory is that this all-American hero had somehow faked his own death.
Ryan's claim is supported by Robert Davis, a life insurance loss adjuster who spent several months compiling a report into the Fossett affair. Both experts believe that several elements of the incident simply do not add up – and their theory is now being supported by an array of aviation experts, private detectives and good, old-fashioned conspiracy theorists.
The faked-death story goes as follows. In the months leading up to his death, Fossett may have been leading what breathless news reports describe as "a secret double life".
There were suggestions that he had opened secret bank accounts, and was cheating on his wife of 38 years with not one, but two mistresses. His finances had also taken a hit after a string of unlucky investments, and the prospect of a messy divorce had left him facing public humiliation and financial ruin.
As Fossett's many previous collaborations with Sir Richard Branson suggest, he was a born showman, meticulous about maintaining a gilded public image. According to the faked death theory, disappearing off the face of the earth would allow him to avoid both fates – while leaving a fitting personal legacy after a swashbuckling career that had started to enter its teatime years.
In addition, Fossett – who had accumulated great wealth but may have hit difficulties – had a $52m motive for going missing: a life insurance policy that would secure his wife's financial future.
Of course, all fishy business has naturally (and stridently) been denied by those close to Fossett, who dismiss it as distasteful speculation by journalists in search of a silly-season story.
Yet the rumours of wrongdoing are not limited to the media. Military people are not prone to hyperbole, and Lt-Col Ryan's comments about the Fossett case (in an interview with the News of the World last weekend) were far from understated.
"Anything is possible," she said. "There are a lot of raised eyebrows; even more so now. I know very few people here, friends in law enforcement, that buy this story like the rest of the world has. I've been doing search and rescue for 14 years. Fossett should have been found. It's not like we didn't have our eyes open. We found six other planes while we were looking for him. We're pretty good at what we do."
Comments made by Davis, who seems to have been employed for a broker who sold a policy backed by Lloyd's of London, were even more damning. "What I've strived to find out is; what happened to this man in the run-up to his disappearance? Why did he disappear?" he told reporters. "I spoke to people who were on the scene, people who were helping out with the search efforts, anyone whom I thought could shed some light on this. And what I discovered is that there is absolutely no proof that Steve Fossett is actually dead.
"I'm not a conspiracy theorist, I'm a man who deals in facts, and I don't really care if he is alive or dead; it makes no difference to me. What I am interested in is the truth – and a proper criminal investigation of this man's disappearance was never undertaken by law enforcement or officials in the state of Nevada."
The truth about Steve Fossett, if it is indeed out there, lies somewhere in a 400-mile radius of The Flying M Ranch, an exclusive and very private flying club about 60 miles south-east of Reno, owned by Paris Hilton's grandfather, Barron Hilton.
In glider-flying circles, the club – at the centre of a million-acre estate, and at the end of a long dirt track guarded by security personal and a lot of "keep out" signs – is perhaps the most sought-after takeoff spot in the world, thanks to strong desert thermals that help engine-less aircraft circle for hours. The Flying M has been used as a flying and fishing base by such luminaries as Buzz Aldrin, Morgan Freeman, Sylvester Stallone and the late John Denver. Other very wealthy amateur pilots make it their regular base.
This was the location from which Fossett set out at between 8.45am and 9am, telling the only witness to his departure – a personal pilot who worked for Hilton – that he was scouting for a location suitable for a planned land-speed record attempt, and would be returning at around 11am. He was flying a Citabria Super Decathlon, a single-engined light aircraft made from wood and fabric. The 1980 model, usually used for aerobatics, could fly at 100mph and had enough fuel to keep going for four hours. Nevada's air traffic laws do not require pilots to submit flight plans, so little is known about his intended destination.
To anyone unfamiliar with the surrounding area, it may seem unlikely – or even impossible – that, in the 21st century, in one of the most technologically advanced countries on earth, a man and an aircraft could just vanish. But a visit to the sprawling Silver State is enough to change your mind. Off the beaten track, which basically constitutes a couple of highways and the casino cities of Reno, Carson City and Las Vegas, an area of Nevada 20 per cent bigger than the entire UK contains little except uninterrupted, mountainous desert.
To the east of the Flying M lies the inhospitable Great Basin. To the south is the vast Yosemite National Park, and to the west, the hills of the Sierra Nevada. It is one of America's most brutal yet beautiful natural wildernesses.
The topography also makes it the perfect place to disappear. It is full of deep gullies covered in a dense mixture of dry scrub and trees, which caused serious difficulties for the airborne search teams. Access on foot is almost impossible.
According to the case against Fossett, the plane he was flying might also have been designed to make a rescue operation difficult. Most of its lightweight structure is invisible to radar and infrared detectors. It is also easily dismantled and hidden.
To add to these circumstances, Fossett took off that day without his usual first-aid kit and with only a single bottle of water. His pilot's GPS watch, which boasts an emergency location device, was left in his bedside table at the ranch. He didn't pack blankets, and was wearing a pair of shorts and a T-shirt.
Although Hilton's pilot, the only man who actually witnessed the takeoff, has never been quizzed by official authorities, reports have claimed that he was surprised to notice that the famous adventurer failed to carry out the aircraft's standard safety check before setting out – a short procedure that might have flagged that its satellite location system was apparently not working.
"We don't want to speculate. Let's stick to the facts," Barron Hilton said this week, in an effort to silence the conspiracy theorists. "That's what we pilots do: facts count, not speculations. Steve had fuel for four hours and flew at 100mph. Those are the facts."
Unfortunately, to many experts these "facts" simply don't add up. The Chicago-based private detective Paul Ciolino was paid by Robert Davis to help on the investigation by providing names and addresses and tracking down one of two women with whom Fossett was rumoured to be having an affair. He stumbled upon a British-born woman who said she'd met Fossett on a commercial flight two years earlier, and had been involved in a relationship with him until his disappearance. She claimed that a second woman had allegedly contacted her after the disappearance, saying she too was his mistress.
"Here is a guy who owns over 100 land and air speed records. He's got electronic toys, satellite locators, all kinds of safety devices coming out of his ears. And we are meant to believe he got into that plane without anything? It goes against everything he's ever done," Ciolino says.
"This plane was crash-proof. You or I could take that plane up in the air, and we would have trouble crashing it. Even if he'd suffered a complete engine failure, he could have guided that thing down. And if it had crashed, it had location electronics that should have meant they'd track it down in hours.
"But people at the highest level of government have got involved in this search, and they have used every ploy known to man to find him or his plane. And they haven't turned up a thing. And if you speak to them, you will find some very suspicious people."
Ciolino, who knows Chicago's legal system, said Fossett's death certificate was issued with almost indecent haste. "I deal in a lot of probate cases involving very large estates, and nothing ever happens fast in them. But that guy got declared dead in world record time. It just doesn't add up."
Other investigators say that Fossett, who had made a fortune in finance before achieving fame through his circumnavigation of the globe in a hot-air balloon, was suffering from the downturn in America's economy. He was rumoured to have invested in troubled firms such as Morgan Stanley and Bear Stearns. Investigators are trawling through his notoriously opaque finances to discover if part of his $20m fortune had been squirrelled away in a secret bank account.
Further questions remain about the decision by Hilton to employ a private security firm to help with the search from his Flying M Ranch. Some reckon it was a splendidly generous gesture (the operation cost several million dollars). Others believe it was designed to keep inquisitive reporters off the property in the aftermath of the disappearance. On the ground, opinion remains divided.
In a baking hot aircraft hangar just north of Reno, Chief Warrant Officer Russ Schuler of the Nevada National Guard shows off the OH 58 Kiowa helicopter in which he spent eight hours a day during September searching for Fossett.
It is equipped with an infra-red sensor that can detect tiny changes in ground temperature, from several thousand feet up. It can land in tiny spaces to despatch a rescue team into the deepest wilderness. In short, it is one of the most state-of-the-art bits of search equipment known to man – and it was one of scores of choppers and planes that were used in what became the biggest domestic rescue mission in US aviation history.
How, then, can Schuler account for the failure to discover so much as a scrap of evidence? How can the many teams, who even searched at night using night-vision goggles, have drawn such a resounding blank?
"I can't. I mean, I don't have a reason. We searched what we could, and in what we did search, we just couldn't find what we were looking for," he says. "But I would say that the terrain makes it very difficult. Each mountain can have a hundred gullies, and each gully you have to go over very slowly. People can go missing there for years. In fact, in the Fossett search, we discovered at least two other airplanes, which had gone down years earlier."
Other rescue workers, many of whom don't buy the theory that their former hero could have disappeared deliberately, say that until you begin searching the dense scrubland in some of Nevada's more elevated areas, its impossible to understand the scale of their task.
"As someone who has a certain experience of the terrain, I was surprised by just how tough going it was," says Simon Donato, who led a search team on foot to Nevada's desert last month. "Each peak has up to a hundred canyons, and you really have to trawl each one to be sure there's nothing there.
"We had two men working either top of a canyon, a couple on each slope, and one person at the bottom. But on the creek bed, it is basically choked with alders. I didn't believe myself that someone could just disappear there, but having now seen the area, and realising how rugged and vast it is, you could see how it would happen.
"That plane was not encased in metal; it was not big, it was a steel cage encased in fabric that wouldn't reflect the light. And if it came down in forest, you would struggle to see it from the air."
Donato adds three further explanations for Fossett's disappearance vanished. He could have crashed in an open area, but the wreckage could have disappeared under a mountainside. His craft could have been burned up in a flash fire. Or it could have gone down in heavy woodland at the bottom of a ravine, where the satellite tracking system wouldn't work.
Mike Larson, a land surveyor at the Department of Interiors in Carson City, Nevada's state capital, has spent almost every free weekend since Fossett disappeared searching for the crash site.
"Steve Fossett was an American hero," he says. "I don't believe the myths: he was a man of integrity. Not all of us are perfect, all of us have issues. But I think he was a man of his word.
"To those who say that things about the trip were strange, I would say this: Fossett was going on a pleasure flight, he wasn't actually experienced in flying a small plane, and he wasn't flying a model he normally flew, so there was no reason why he should be particularly adept, and no reason the crash shouldn't have happened. His final journey was like taking a Corvette around the block for a spin."
From the air, the Nevada landscape can also create a "Bermuda triangle" effect that causes planes to crash. "A number of canyons in the area are effectively dead ends: once you fly into them, they aren't wide enough to turn in, and if you can't climb at the 500ft a minute you would need to exit by carrying on in a straight line, you are basically doomed once you get into them."
Larson has now narrowed his search to a 10 mile square section of desert south-west of Hawthorne, where he says he is "90 per cent" sure the plane came down and can now be found, after poring over thousands of map co-ordinates and pieces of evidence.
This week, Sir Richard Branson called Fossett "one of the most generous, good-natured and kindest people I have ever met," and announced plans to name his recently unveiled spaceship The Spirit of Steve Fossett.
Like most of the great explorer's friends and family, he'll be hoping Fossett's plane will soon be found in that shimmering Nevada Desert. Otherwise, the Steve Fossett "spirit" may become irreparably tarnished.
The Reggie Perrin files: great vanishing acts
* In 1967, the Australian Prime Minister, Harold Holt, disappeared after diving into the sea near Melbourne. He was considered a strong swimmer and his body was never found, leading to theories that he'd faked his death. The most outlandish explanation came in 1983, when the British journalist Anthony Grey suggested in his book The Prime Minister Was a Spy that Holt was a Chinese spy and had been spirited off to Beijing in a submarine.
*John Stonehouse, a Labour MP, disappeared in 1974, leaving just a pile of clothes on a Miami beach. In fact, he'd gone to Australia with his mistress. He hit the headlines again later that year when, after his capture in Melbourne, police thought they'd collared Lord Lucan.
*A life-insurance scam went tragically wrong for American businessman William Stewart in 1985, when he died after driving his rented car into a lake near Lucerne, Switzerland. Stewart's carefully planned "suicide" was thwarted by the car's childproof locks. Trapped, he drowned.
*Perhaps canoeist John Darwin was inspired by British businessman Paul Early, who in 1992, apparently inspired by Frederick Forsyth's novel The Day of the Jackal, faked his death at sea and used a dead man's identity to slip into France. Early was caught hiding in a hole in the floor under his bed after returning to Britain to be with his wife, who, like Anne Darwin, was in on the plan.
*Moana Pozzi, Italian porn star, was reported to have died of cancer in France in 1994. In 2005, an inquiry was opened in Rome as rumours persisted that her "death" was a sham to cover up links to a top politician, but its findings were inconclusive.
*In 1999, Karl Hackett tried to pretend he'd been killed in the Paddington rail disaster. His cousin revealed his new identity to police, and he was given a suspended prison sentence in 2000.
*Hong Kong resident Steven Chin Leung was arrested by US marshals in 2002 after it emerged that he'd fabricated his own death in the chaos of the September 11 World Trade Centre attacks. He was caught trying to obtain his own death certificate, posing as his (non-existent) brother.
*In March 2008, Latvian police were quick to suggest Russian-born Leonid Rozhetskin had faked his own death. The millionaire vanished from his villa, and the mystery deepened when there were sightings of his private jet. Detectives are now investigating the possibility that he was the victim of a contract killing.