Perhaps the cost, revenue and operating costs between the airport and the City of Calgary could be split based on ridership as a joint partnership?
There are 31,753 trips generated daily by the airport, and a further 30,000 trips generated by the employees. This is 61,753 trips daily generated by the YYC.
I'd be curious what the % modal split for the airport would be. Assuming 12%, (less than Calgary as a whole at 17%, the airport on the one hand needs inbound to have transportation, but parking at the airport is also relatively cheap compared to downtown), then the total trips per day would be 7,410. This is comparable to other moderately heavily used C-train stations locations.
Number of Employees
http://www.calgaryairport.com/Default.aspx?cid=247&lang=1
Passenger Statistics
http://www.calgaryairport.com/Default.aspx?cid=117&lang=1
Modal Split
http://www.calgary.ca/docgallery/bu/trans_planning/data/2008/mobility_monitor_april.pdf
Ridership by C-Train Station (Weekday Ons and Offs)
http://web.archive.org/web/20070608132311/http://www.calgarytransit.com/html/lrt_ridership.html