I was in my mid to late thirties when I heard the bats at sunset hunting insects over a river, between two rows of trees - presumably Noctules.
I found them from their squeaking - but no one else who'd been at the event came with me when I went to investigate - because they could not hear anything.
It was rather memorable to watch them scooting up and down the length of the avenue of trees, so wonderfully agile in flight.

The local pet shop used to sell dog whistles which were supposed to be silent, for Humans - but I could hear them. These days I have tinnitus thanks to my neighbour firing a starting pistol at me, but I suspect that my hearing is still pretty acute.