The 'object' made an extremely high speed turn which would be impossible with our traditional technology even today.

Approximate time shown (it happened more than half a century ago). Walking along with friend in a northerly direction on the left bank of the Danube river of South Budapest. The river flows at this point quite accurately in the N-S dirction. We both were engineering students, the school was out, absolutely perfect day - no clouds, bright sunshine.  Discussing some technical problems, we stopped for a few seconds and turned around. With amazement, we saw a brilliant spot on the sky at about 35 degrees elevation about 245 degrees direction - the sun was now behind our backs. It was impossible to judge the distance of the spot, but it exhibited strong flickering light from it assumed to be the result of the air mass turbulence, similarly to star watching, indicating several miles. There were no aircraft of any kind in the vicinity. The size of the spot was approximately 2-3 times the diameter of Jupiter as can be seen from Earth. We do not know, how long the object was there before we noticed it, but it was stationary, no movement detected when we spotted it. It hung there for about 30 seconds or so, then very slowly drifted to the right from our vantage point - to the Westerly direction, and stopped for several seconds. After about 15 seconds, it started out in the same westerly direction, accelerating very rapidly, after moving about 15 degrees at an extremely high speed now, it took an abrupt turn 90 degrees to the North (from our position), kept moving with extreme speed, then slowly faded out.
It was a Communist system in command at that time in Hungary, but apparently it overlooked the press report, because it reported that 200 thosand people called in about this phenomenon. That was the first and last official report on the subject.
The most advanced aircraft at that time in that region were the Mig series (15, and up) Russian vehicles, somewhat later. The only rockets at that time were the German V1 and the V2 rockets. At any rate, the extrmely high speed right angle turn (could not see any turning radius whatsoever) would have torn apart any conventional earthly craft by the lateral vector. I was speculating as to whether it could have been an aerial phenomenon - concentrated ligt focused overhead, etc. - but I had to discount these theories, I found no credible report on such phenomenon in the scientific field in the past 50 years. I have never reported this event before.
Date is approximate.  PD