There are other accounts on the forum about men regaining their places in their aircraft after falling out, but alas I don't remember the names. I'm sure some kind sole will leap in having completed a search.
The best known such escape, and undisputed AFAIK, is that of Louis Strange. Flying a Martinsyde S1 scout with a lewis gun on the upper wing (about April 1915), he reached up to change the drum, the aircraft inverted; he fell out, found himself hanging by his fingertips from the Lewis drum (no parachute at all), but managed to lift up his feet, and kick the control column so that the aeroplane rolled upright and he fell back in.
One summers afternoon in 1917 Grahame Donald attempted a new maneuver in his Sopwith Camel. He flew the machine up and over, and as he reached the top of his loop.....
this story or a very similar one has been discussed on this forum before. There are doubts on several levels. If there was no longer back pressure on the control column, why would the Camel complete a loop? Its natural tendency would be to enter a vertical dive, not go beyond the vertical underneath its falling pilot. And with the Camels well-known gyroscopic effect it is very unlikely to have remained in the same vertical plane and ended up under the pilot.