Pilots of an early summer plane were left baffled after spotting a mystery "flying" man whizzing past their aircraft 3,500 feet above the town of Macclesfield, United Kingdom, a few months ago, according to UK MailOnline.

Famously dubbed by the public as the "Superman of Macclesfield," the incident has been shrouded in mystery since it was reported by the pilots of the plane.

On June 13, pilots of the massive Airbus A320 were heading towards Manchester Airport when the unidentified flying man came out of nowhere within 320 feet of the plane. For the couple of seconds that he was visible within 300 to 600 feet of the fuselage, the pilots and other crew members saw no signs of a canopy suspending him.

It was later examined and confirmed that the man had not been detected on the radar, with further checks failing to reveal the deployment of a parachutist, paraglider, skydiver, or balloonist in the immediate area at the time, which suggests that the airborne man used some sort of wing suit, according to Bold Ride

"They first sighted the object a few hundred meters in the 11 o'clock position 200 to 300ft above," The Airprox Board, which is responsible for looking and analyzing airborne near misses, said.

"It passed down the left-hand side of the aircraft at 100 to 200m. The crew only saw it fleetingly, there was no time to take avoiding action and they based their assumptions on it being a person under a canopy. But neither can remember seeing a canopy," the agency added.

According to the official report on the June 13 incident, it was "unfortunate" and "frustrating" there was "no way of corroborating what the pilots had reported."

The flight crew "couldn't be certain that it wasn't a person-shaped balloon," the report added. 

Meanwhile, aviation expert Chris Yates said, "It is a complete and utter mystery."