Pilots on a passenger plane were stunned when a “flying man” zipped past the side of their aircraft at 3,500ft as they flew over Macclesfield.
Aviation experts admitted they were baffled by the sighting of the human UFO, who has been dubbed the 'Superman of Macclesfield'.
He appeared from nowhere as the Airbus 320 passed above Broken Cross and towards central Macclesfield while it was coming in to land at Manchester Airport.
The pilot and first officer, who reported the sighting to air traffic control, thought the man was a paraglider but could not see a canopy. The allegedly airborne man was above the Rainow area when spotted.
And the mystery deepened when there was no sign of him on radar.
Further checks failed to find any paragliders, parachutists or balloonists in the area at the time.
Officials at the UK Airprox Board, which investigates near-misses in British airspace, admitted that the mystery may never be solved.
Describing the pilots’ account, the report said: “They first sighted the object a few hundred metres in the 11 o’clock position 200 to 300ft above.
“It passed down the left-hand side of the aircraft at 100 to 200 metres.
“The crew only saw it fleetingly, there was no time to take avoiding action and they reported that they based their assumptions on it being a person under a canopy.”
At the time, skies were clear and visibility was about six miles, the report said.
But it added: “Neither can remember seeing a canopy.”
Air traffic controllers on the ground could also see nothing on their radar screens at the time of the incident at 1.30pm on June 13.
And experts from the British Hang Gliding and Paragliding Association said weather conditions at the time would have made it impossible for a lone flyer to be in the area.
They also told investigators the pilots would probably not have missed a canopy or parachute as it “would have been the most obvious object by a significant margin”.
The report added the pilots “could not be certain that it was not a person-shaped balloon” but that was also unlikely in the conditions.
It concluded: “The board agreed that it was unfortunate that there was really no information that could lead to identifying the unknown object.
“This was frustrating to both the board and the pilots concerned, who had clearly seen something or someone, but there was no way or corroborating what they had reported.”
The incident was not the first sighting of human UFOs.
In April a figure was filmed flying over people in Qutub Minar, India, and the video quickly went viral on the internet.
Closer to home in Staffordshire, another man was spotted soaring over Cannock Chase in February 2009.
Five people contacted the local newspaper and described it as a “Superman” moment, with one believing he was using a James Bond-style jetpack.