I have made an inquiry to Aeroplan about the web site's ability to find award seats between any city pairs. They indicated (which was already my personal experience) that the web site does not necessarily give all Star Alliance carrier awards, for all city pairs; this display of the other Star Alliance carriers is especially limited on those 2 city pairs which AC flies. For example, I have yet to find award availabily on UA or US between a Canadian and American city pair.