I read a story in a book on aviation mysteries, Ralph Barker or someone like that.
Essentially a man who had been drinking earlier boarded his 150 for circuits from a Scottish airfield one winter night. Only for the aircraft to disappear forever, not him though. A few weeks later his body was found on a heathery hillside. After a post mortem he was found to have some injuries but in fact had died of exposure???? Of the aircraft there was no sign.
The only explanation they came up with was that he had been drunk when he took off and had not secured the door or the seatbelt. At some point perhaps he had leaned on the door only to depart stage left. The aircraft unburdened but probably in trim climbed away to the nearby ocean to ditch once it ran out of fuel and disappeared.
Incredibly it seemed he survived the fall, soft heather and a slope might have helped in this. Only to die of the cold on the hillside.
Of course he may have jumped Quite a story!