Hey, I was there for one of those! at I think its about 05:40 in the video you see one aircraft slice another one off just behind the cockpit.
As I recall it was 1993 at RAF Fairford, It was a pair of blue Mig29 fly by wire protytpes. I was at the far east of the runway not very far from the end of a row of a dozen or so Hercules, just at the end of the spectator area. One of the Mig29's crashed into the Hercules at the other end of the row. New underpants time

It was about a mile walk back to the car and rest of family at the other end of the runway. It was kind of strange as the few of us who had been closest to the impact just wanted to leave, while thousands of other people were pushing past going the other way for a closer look!
Edit: I found a better video of it on youtube:
Ironically, the video commentary is incorrect, it was definitely Fairford, Gloucestershire.