From our top field in Yorkshire we can see on a clear day with Binoculars' the Humber Bridge support, around 70 miles. As for A/C we can easily see north bound turning A/C with landing lights on from East Midlands Airport a similar distance. As for the high level stuff it always has amazed me both the view from the A/C, but also looking at the A/C as to how far away vertically they are.
Cheers
Mr Mac