What makes their accounts so hard to believe is the recurrence of the phrase 'flying saucer'. There's no single explanation for all UFO sightings, but there is evidence to suggest that man-made craft are behind some of the more famous cases.
Since the 1930s engineers have tried to develop high-performance aircraft, capable of taking off with little or no runway and without fear of interception. Their research into low-aspect-ratio aircraft, or 'flying wings', led them to design and fly aircraft that even today look futuristic, almost alien. Their designers saw these craft, with their high manoeuvrability and short or vertical takeoff and landing (S/VTOL) capability, as the fighters, the spy planes and long range bombers of the future.
Their thinking is reflected in the boomerang-shaped Northrop B-2 Stealth Bomber and proposed unmanned combat air vehicles (UCAVs) for the next century. Other low-aspect-ratio aircraft had a circular footprint or 'planform' and were nothing less than flying saucers. Anyone who thinks this is a bit farfetched should note there is a special US Patent (Class 244, Aeronautics: sub-class 21.2 Airplane, circular) for aircraft using a circular wing planform.
Best known were Charles Zimmerman's propeller-driven flying pancakes designed for the US Navy, starting with the small V-173 in 1942, then the more advanced Chance Vought XF5U-1. Officially this aircraft never flew, but one of Vought's designers, Thomas Smith, says that it was flown many times before being taken to what is now the Edwards Air Force Base (AFB) in California, and that secret jet powered versions were also designed. Back in the early 1930s the pioneers were dogged by low level funding levels and problems with engines and stability, but the downfall of the Third Reich was catalyst for further development.
Classified reports from technical intelligence teams sent into Germany even before the end of the war filtered back to the Allied commanders. These reports described top-secret research laboratories of an enormous scale and sophistication, like the Hermann Goering Aeronautical Research Institute at Volkenrode.
Under top-secret operations such as Overcast, Paperclip and Lusty, German scientists, whose research had been well funded by the Nazi war machine, were recruited to continue their work in the United States and, to a lesser extent, in Britain, and France. Russia mounted US-scale efforts such as Operation Osvakim. This meant both sides in the forthcoming Cold War now had key scientists, research aircraft, equipment and truckloads of design paperwork.
The father of the German disc program was Rudolph Schriever, a Luftwaffe aeronautical engineer assigned to Heinkel in 1940. Influenced by Zimmerman's designs, his ambition was to develop a disc shaped VTOL aircraft. Schriever's ideas soon came to the atention of Ernst Heinkel, who encouraged him to design a model prototype, the V1, which was immediately classified top secret after its first flight.
Funding followed for a full-size piloted version, the V2, which first flew in 1943 with Schriever at the controls. Thirty feet in diameter, the V2 had a fixed central cabin around which a ring with adjustable vanes rotated to provide thrust in both the vertical and horizontal planes. Some drawings show a vertical tail fin at the rear of the cockpit.
Early in 1944, Schriever's top-secret programme was moved to Czechoslovakia and set up in two factories, with most of the work taking place outside Prague. Schriever was joined by a number of leading aeronautical designers and engineers, including DR Richard Miethe (who had worked with Wernher von Braun on the V1 and V2 missile programmes at Peenemunde), Italian physicist Dr Giuseppe Belluzzo and Klaus Habermohl (a specialist in gas turbine technology). Another addition was the Austrian scientist Viktor Schauberger, who just before his death in 1958 claimed to have worked on a highly classified US disc programme in Texas.
This expanded team built an even larger disc the V3, which was completed by 1944 and is said to have been much more technically advanced than its predecessors. In postwar interviews Schriever said it had a full VTOL capability and was powered by a Habermohl designed radial flow turbine that rotated around the cockpit, ducting exhaust gases below the vehicle to provide vertical lift and through vents around the rim when in level flight. Nothing is known about V4, V5 and V6, which probably never went further than the drawing board, while the fate of the more advanced V7 and V8 discs is even more mysterious. Under operation Paperclip most of von Braun's rocket team were transferred to Fort Bliss in Texas. Exactly what programme Miethe was assigned to is still classified, but many leading German scientists, including Alexander Lippisch, designer of the first delta-winged aircraft, were stationed at both there and at Wright Field (now Wright-Patterson AFB).
Miethe's presence in the United States was confirmed in a television interview for the American series Sightings, when the former assistant secretary of the USAF Alexander Flax admitted he had been brought to the US after World War II to work on flying discs. Flax confirmed that several such programmes were under way at that time, including at least two other high-priority flying-saucer projects, one stemming from the Zimmerman Flying Pancakes. But there were problems: the Pentagon, keen to keep its disc programmes tightly under wraps, did absolutely nothing to discourage the attention-deflecting public belief in alien visitation. This policy compromised the project's secrecy - for every subscriber to the alien theories there might be someone sane enough to realise there could be a perfectly rational explanation to the curious sightings of disc-shaped aircraft. At the time though it suited the Pentagon to use UFOs as a blind. A further problem was that major advances in the USSR's saucer development led the CIA to predict the imminent penetration of United States airspace by Soviet reconnaissance discs.
It was decided to relocate the next programme to Canada, where discreet, but complete, United States control could be maintained. Avro-Canada in Toronto, a UK-owned company specialising in developing advanced military aircraft, had all the necessary skills and experience to run a top-secret US project.
According to one reliable Canadian source, a team of specialists from Wright Field (including Miethe) made the first of several visits to Toronto in late 1951. The following year, in Ottawa, a secret contract to develop discs was signed between Avro-Canada and the Canadian government and it is believed that Miethe moved to Toronto. From the start of the programme in 1953 Canadian newspapers reported that Avro-Canada was working on a flying saucer programme, a claim that officials vehemently denied.
Sources told the Toronto Star of Project Omega, an aircraft that was powered by a revolutionary ring-shaped gas turbine that rotated round a central cockpit. Within months US correspondents began to suggest thae saucer was mainly funded by America. The Canadians unexpectedly announced in 1954 that all development of disc aircraft at Avro Canada had been cancelled. Rising costs were cited as this reason, but a year later USAF secretary Donald Quarles confirmed that negotiations were underway with the company to start full-scale production of a combat disc aircraft. In 1960 the alleged product of this seven-year multimillion dollar research by a world leader in aircraft design - the Avrocar - was unveiled. But it bore no resemblance whatsoever to Quarle's high-performance combat disc, as it was little more than an 18ft diameter, unstable hovercraft. Belief began to grow that it had been built to deflect public interest from a 'deep black' programme.
In late 1995 Jack Pickett was instrumental in securing the partial declassification of a top-secret US Airforce programme, Project Silver-Bug. It revealed two flying saucer designs that seemed to be part of the Avro-Canada programme. Of special interest is Project Y2, described as a 'VTO flat riser'. Just 29ft in diameter, the maximum speed was Mach 3.5 at over 80,000ft impressive by present standards; sensational back in 1955.
While the powerplant described for Y2 was similar to the radial flow gas turbine built by Habermohl at the BMW factory during Word War II, an even more advanced concept was being studied. Declassified documents refer to an electrogravitic propulsion system for Project Winterhaven, a supersonic disc that's capable of sharp changes of direction during flight. The programme was officially cancelled, but the documents show this form of propulsion was the subject of intensive research.
Which brings us back to Jack Pickett's encounter with flying saucers in open storage at MacDill AFB in Florida back in 1967. Under the blistering sun, looking sadly neglected and with flat tyres, stood four discs of similar design, varying in diameter from 30ft to 100ft. On either side of the central canopy, which tapered to a vertical tail fin, air intakes were blended into the disc' upper surface with exhaust outlets for the turbojets visible underneath at the rear. Conventional control surfaces were apparent and each one had a tricycle undercarriage. All four had USAF insignia with 'X-perimental' on the disc and 'UL' on the fin. Pickett was initially told the Pentagon was considering declassifying the old discs and later given clearance to write about them in two magazines he published for the USAF. While two armed guards stood outside, a senior officer told him they were supersonic spyplanes and from the many photos he saw some were more advanced than those at MacDill.
Nothing was disclosed about who built the discs (although U was the manufacturer's code letter for Vought and L for Bell until 1962). Apparently, the early problematic test flights were responsible for creating the 'Saucer Flaps' and UFO crash stories.
Just as Pickett started work on his article, a new disc ran into difficulties after take-off from Avon Park AFB in Florida. Local papers reported UFO sightings, with the result that the Pentagon decided against declassifying the discs. A senior officer collected all the photographs as well as the early drafts of Pickett's article, the discs disappeared and every was ordered to say absolutely nothing.
The strict compartmentalisation of these disc programmes may have backfired in 1947 when a press release issued by Roswell AFB in New Mexico stated that the wreckage of a flying disc had been recovered - a release that was quickly withdrawn by high level intervention. A massive security operation was mounted with the disc becoming first a weather balloon, then a top secret Project Mogul balloon. Rumours of recovered bodies were explained as high-altitude crash test dummies in the USAF's Roswell: Case Closed' report of 1997.
Report co-author Captain James McAndrew said a Mogul balloon was the definitive explanation. Later he appeared to change his mind, saying that he'd found documents suggesting another secret project may have caused the crash and cover-up. McAndrew said it combined Japanese balloon technology with a manned glider and was intended for high altitude spyflights over the USSR. Once the pilot cleared hostile territory, he would detach his craft from the balloon and glide to a friendly landing site.
Whether the glider was destroyed by its crew after running into difficulties in the thunderstorm, or whether the explosion was accidental, is hard to tell. And if it was a glider, why were commentators so adamant that the resulting debris was that of a disc aircraft? The only real hope of finding out is to persuade more of the ageing disc plane engineers to tell their story, but they're reluctant to talk to the press. One of the men we spoke to is aged 80 and has, in his own words, 'nothing to lose', but he won't let us name him. Such is the secrecy that still surrounds disc planes.