In 1991 an unidentified craft, travelling at high speed, was said to have entered Russian airspace. Four jets, including one outfitted with a video camera, and three other MIG-21 jets, were scrambled in order to intercept the object. This declassified video footage shows the object as it appeared from the cockpit of the camera plane. It appears to be a large, cylinder or cigar-shaped UFO, travelling at similar speeds to the jet (550 knots). Suddenly it increases its speed and moves off camera, outpacing the jets considerably.
According to the pilots involved, they estimate that the UFO must have reached at least Mach three in about ten seconds. The UFO is estimated to be about twice the size of the MIG-21s. With the technology available to either the Russian government or the United States government at the time, it should not have been able to move as fast as it does, experts say.Video link
UFO