I was lucky enough to be a special guest at the launch of the first MiG-21 in Australia, in the early 1990;s. The aircraft was so loud in afterburner we thought it had blown up!
The impressive acceleration combined with its diminutive size meant that it disappeared from sight very quickly. So quickly that it was difficult to pan my camera fast enough to keep it in view. A few seconds after takeoff it had literally disappeared. It was frightening to imagine being on the receiving end of a ground attack by jet aircraft... by the time you heard the sound and looked up it would be raining trouble!
The MiG-21 cockpit