Some years ago I spent some time in the paddock of Donington Park race circuit, which lies a stone's throw from East Midlands airport. The paddock was (presumably still is) completely surrounded by tall, flat metal fencing, the only gaps being for the gates in & out. The airliners were landing from overhead that day: whenever a 757/767 flew overhead it left behind the most curious whistling, roaring echo that reverberated around the paddock and persisted long after the aircraft itself had disappeared. Other aircraft were just...other aircraft. A bit noisy as they were so low but no trace at all of the mysterious echo.
(chevvron, BOAC never operated the 4c: 4 only I'm afraid)