Mysterious object photographed over Lake Cote, Costa Rica.
The UFO was only discovered after the film was developed. None of the four people on the plane noticed anything odd during the flight.
The shot has been examined extensively but nobody has come up with a reasonable explanation for what that weird disk thing is. It's not a double exposure, and the orginal negative shows no sign of tampering.
Maybe it's a flying hubcap? If so, it would have to be a very high-flying one. The plane was at 10,000 feet when the photo was taken.
ALSO ON THIS DAY
* Rodi Avalanche
Reference: ufo-chronicles.blogspot.com