…or the RAF Lakenheath incident of 1956.
This is again a very good and well documented UFO case involving both visual and radar contacts. It was one of the case analyzed by the infamous Project Bluee Book (US military radars were involved hence their interest) and even they had to throw in the towel and call it "unknown".

…or the RAF Lakenheath incident of 1956.
This is again a very good and well documented UFO case involving both visual and radar contacts. It was one of the case analyzed by the infamous Project Bluee Book (US military radars were involved hence their interest) and even they had to throw in the towel and call it "unknown".
I’ll summarize the story. During the night between August 13 and 14 1956 the control tower at RAF Sculthorpe contacted radar control at RAF Lakenheath (leased to the US Air Force at the time) to confirm contact on a very fast target approaching their position. A military C47 cargo plane crew confirmed visual sighting of a "blurred light" moving at about 5000 ft.
The Americans had a powerful and sophisticated (for the time) CPS-5 radar at Lakenheath and were able to confirm a very good target performing the now familiar incredible feats of acrobatic: breathtaking (ie no build up of speed) acceleration, becoming completly stationary, performing very tight turns etc.
Given the duration of the sighting and its vicinity to sensible military installations (RAF Lakenheath was home to nuclear armed B47 bombers) and having ruled out an "angel" (ie radar echo) RAF and USAF command centers were alerted.
After 45 minutes (this drew much criticism from the Americans) RAF decided to dispatch two Venom NF.II night fighters to intercept the "bogey" (ie unidentified radar target). These two airplanes got to the area separetely and each one was able to get both visual and radar lock on the UFO. The RAF files haven’t been released yet and it’s possible they were destroyed in the ’60s so we’ll probably never have the pilots’ report with the object description.
In each case the UFO "toyed" with the Venoms, first allowing gun lock, then jumping on its tail with a fantastic maneuver and following it closely (200 to 600 ft according to radars) despite all the attempts to shake it off. The first Venom returned to the base because it was low on fuel and the second cut short its operation following "engine malfunction". Comprehensively the pilots sounded "pretty shaken".  
The UFO did not attempt to follow the Venoms, lingered in the area a little more and then departed.
As I said both USAF specialists and the scientists working on both Project Blue Book and the Condon Report proved unable to crack the case despite all their efforts. 
Other cases around the world involved UFOs putting on terrific dogfights with military planes after being tracked by radars: confirmed cases come from Iran, Korea and Belgium.
Finally allow me to repeat once more that I personally believe UFOs to be what the acronym says: Unidentified Flying Objects, something we still aren’t able to identify despite all our best efforts. The Condon Report was a disaster precisely because Dr Condon set out to disprove the "extraterrestrial hypothesis", not to simply analyze the datas laid in front of him and perhaps admit "this is something we’ll be able to understand only after further study".
A lesson still unlearnt on both sides of the fence apparently.