@annabenedetti Here's the link to the article on that:
On September 4th, 1971, on board a twin-engine Aero Commander F680 aeroplane, an automated camera captured an image of a “flying saucer” which to this day has never been successfully debunked.www.uapmedia.uk
Thanks, that's it. They have the link in your article here to the New Yorker article I'd read that mentioned it:
New Yorker, “How the Pentagon Started Taking UFOs Seriously”, by Gideon Lewis-Kraus
- which is the first I'd heard of it. After reading the NYer article, which doesn't show the photo, I had to go look for it.