Research news
Bitesized UFOs #083: UFO Interception Over Minnesota
May 1955: the radar operator onboard an 11th FIS F-89D Scorpion interceptor detected a strange object on his scope during a routine flight. The capabilities and maneuverability of the unknown object were sufficient to warrant study by Project Blue Book, the third official USAF UFO investigation program. Another little known case brought to you by Bitesized UFOs.
See more (external link) 
https://www.youtube.com/watch?v=vYjnOR7pKEQ