A witness sketch of a diamond shaped UFO released by the MoD
The files contain lots of clippings from magazines and newspapers about possible top secret new aircraft.
The articles were diligently collected even though the US Air Force had briefed the MoD that many of the claimed secret planes did not exist.
Eventually all the files will be declassified and made public, but UFO sightings continue, Harriet Rogers and her father Barry filmed a mysterious pulsing globe-like object near their home in Shropshire in February.
Harriet told Sky News she's convinced the object is alien: "It's definitely come back in the same place, literally every starry night."
Included in the files is a photo taken from an RAF Harrier jet of a UFO seen in 1990 by many people near Pitlochry in Scotland.
The MoD took the unusual step of briefing ministers about the sighting.
There are some more unusual reports in the 1200 or so files, like the woman who encountered an alien while walking her dog near Norwich.
She said the alien spoke in a "Scandinavian type accent."
There were several reports of a UFO above London in 1993, it was eventually explained as an illuminated airship being used to promote a new car.
Nick Pope used to be in charge of the UK's UFO files, he now writes books on the subject.
He told Sky News: "While most UFO sightings turned out to be misidentifications of something quite ordinary, around 5% were assessed as unexplained."
Ultimately all of the UK's UFO files will be made public.
Despite them being largely mundane, enthusiasts will continue to believe there is more information being withheld.
While still very interesting these papers probably tell us more about the MoD's priorities during the cold war than about the real truth regarding UFOs and aliens.