X-Files fans, conspiracy theorists, and the tinfoil hat crowd were right all along! Sorta… In the 1950s, the US government really was building a flying saucer. But it didn’t involve little green men, human-alien hybrids, or David Duchovny; this isn’t what you’d call a "smoking gun."

The good news: Declassified government documents describe a secret military aircraft that bears a striking resemblance to a UFO. The bad news: The proof-of-concept vehicle (which, itself, was declassified for years) had a flight ceiling of 3 feet and was cancelled after 3 years and $10 million dollars flushed down the toilet. So it’s highly unlikely that any witnesses saw it hover in the sky. 

There’s also the issue of timing.

The Avro Canada VZ-9 Avrocar program lasted from 1958-1961. The Roswell sighting allegedly happened in 1947. So there’s that. But I'm the serial UFO devotees would point to incidents that occurred before and after.

In the early 1950s, the US Government became infatuated with vertical take-off and landing (VTOL) aircraft. If the Cold War turned hot, the US assumed its adversaries would launch tactical-nuclear first strikes against its airbases, crippling its ability to retaliate. In such a scenario, runways (and paved roads in general) would be at a premium.

About this time, British aircraft designer John Carver Meadows Frost (aka, "Jack" Frost) began experimenting with the Coandă effect, or the idea that a fluid jet adheres to a nearby surface and follows its contour (according to the British Journal of Anaesthesia).

This led to the idea for a disc-shaped craft, where the exhaust flows up and over the entire surface of the body.

The Avrocar S/N 58-7055 (marked AV-7055) on its rollout.
The declassified documents for Project 1794 (or Project Y-2) specify the original requirements based on the calculated thrust potential of the design as follows: top speed between Mach 3 and 4, flight ceiling over 100,000 feet, and range of about 1,000 nautical miles. The military leaned on Canadian company Avro Canada to build their ambitious design.

These same documents described their design thusly:

"The proposed design was for a jet-propelled all-wing aircraft of circular platform, embodying a new arrangement of a turbo-jet engine and employing jet control. In order to separate the engine development task from that of the airframe an intermediate research vehicle employing 8 small conventional turbo-jets radially disposed like the spokes of a wheel was also proposed at this time."

It continues, describing the mode of operation:

"This ducted fan arrangement – while preserving the radial flow and circular planform [sic] with air cushion VTOL, avoided some considerable objections to the earlier designs and also gave good static thrust-lift efficiency and a very thin wing, using the entire depth of the wing between skins for engine air flow." 

While the project was in development, Jack Frost suggested a smaller, proof-of-concept test vehicle — hence, the Avrocar.

The Air Force wanted a supersonic jet while the Army wanted a flying jeep. It ended up being neither.

Following multiple redesigns, the Avrocar still couldn’t hover more than a few feet off the ground without wobbling uncontrollably, and as Popular Mechanics points out, it’s a bad idea to build an aircraft with an aerodynamic center far from its center of gravity.

You really have to pity the tinfoil hat crowd — they had the Holy Grail in their grasp, before having it cruelly snatched away. One such individual wrote me a few years ago, and I keep it on my desk as a reminder of human absurdity. It reads, in part:

"My request is simple, but also extraordinary. Enclosed is some information about the topic, alien abductions, and a report on my progress in stopping alien abductions. Although I can’t prove that UFOs exist or any related material is positively true, I have enough reports from people to convince me that it is and to keep making what I call 'thought screen helmets.'"

Poor, misguided souls.

It appears that the truth is still out there (or right in front of your nose for those who care to look).