I've ridden airport trains in Chicago and Atlanta, and vast majority of traffic seemed to be airport workers, with no passengers sporting luggage. Which makes sense give the size of those airports. I've used the Hong Kong airport train, and that one had a lot of travelers, but that's a different situation. Here in Calgary there is still a lot of parking for airport employees, and probably enough bus service to get employees there. I'd much rather see money go to the Green Line or to putting the Red Line underground downtown.