Interestingly, high-altitude testing of our reconnaissance aircraft had an unexpected side effect—a tremendous increase in reports of unidentified flying objects (UFOs).

Strange things in the skies in the ‘50s & ‘60s? That was us.https://t.co/RN0Y6uRIds#WorldUFODay #HISTINT pic.twitter.com/apJcuxnPRv

— CIA (@CIA) July 2, 2019