Calgary Transit
Calgary Transit has regular service to the Banff Trail station. Fares are low and represent a convenient alternative to driving. It is especially helpful if you want to avoid renting a car if arriving by plane. Transfers are also good for any of the many bus routes and the 7th Ave. corridor downtown is a "free fare zone."
Banff Trail station is on Route 201 (Somerset-Bridlewood / Dalhousie) on the Dalhousie end of the line. The full run goes through downtown, past the Calgary Stampede grounds and well south of downtown. On 7th Ave downtown area there are many stops where you can transfer to the other line (202; 10St./Whitehorn) which goes from downtown northeast towards the airport (though it doesn't connect to the terminal directly).