Britain from above is a new site with aerial photos from the 1919-1953 era. Seems to have a lot of potential although it needs some tuning to speed up the searches 
Nothing much from my part of Northumberland on it yet, but there are some interesting views of Newcastle-upon-Tyne among its 16000 pictures. Had to resort to using it on the laptop as the click on the map is not functional on the ipad.
Digging up the ancients
Crackett, Webb, Turner, Henderson and further back
