Catbus created this Google Map that allows you to view 1947 aerial imagery of down-town Montreal on Google Maps. Using the map it possible to compare the 1947 aerial imagery with
Google's satellite view. You can view the map in full-screen mode here.
The University of Connecticut Library created this cool application that allows you to view historical aerial imagery of Connecticut from 1934 side-by-side with Google Maps 'satellite view'. The application also allows you to view more modern aerial photo maps from 1990, 2004, 2006 and 2012.
1930's New Jersey
The New Jersey State Atlas is a Google Map that includes the option to view aerial imagery of New Jersey from the 1930's. The map includes a slider control that allows you to adjust the opacity of the historical aerial imagery and make a direct comparison with the modern day Google Maps 'satellite view'.
Old Maps of Moscow contains a large collection of historical maps and aerial imagery of the Russian capital. The 1940's aerial imagery shows Moscow during the time of the Second World War.