Pilot Romain Jantot was flying over French Guayana in a super-light aircraft when he noticed an unexpected passenger hanging out on the wing. (This takes place about 50 seconds into the video.)
Needless to say, the pilot immediately returned to the airport and managed to land, all without the cat ever falling out of the aircraft.
In the video's description, Jantot described the situation in French. Translated, the description reads:
It was a routine baptism until... That's why it's important to look at the wings before each flight. FYI the cat is fine. It continues to fulfill its role as club mascot.
CNN has a more in-depth video on this video. Check it out here.