I lived in a fairly remote cottage on the side of Wensleydale for about 20 years and got lots of air traffic passing night and day. As long as the Herc and Chinooks weren’t that high and fast we found them quite quiet, even multiples with few lights on sometimes sneaked up unannounced at night. But put them at 1000 feet and fast, you could hear them for ages. Not as bad as the F15s though, they were noisy.