GRT to Airport?

[plam]

For time savings, YKF only works (in general) if there is a direct flight to your destination: once you add a connection, it dwarfs the additional driving time.  It's the same reason I fly to SFO to get to silicon valley rather than SJC.  (And, yes, there would be exception in cases where there is a connection from YYZ as well.)  Unfortunately the number of direct flights is still fairly limited, so the number of passengers (for flights and for transit) will also be fairly small.

You are all assuming driving is a viable (and the default) option. I don't own a car and I fly 4-5 times a year. Yes, I have wonderful friends who will drop me/pick me up from YKF and even YYZ on occasion - but if i'm landing in the middle of a workday that isn't an option. I often take transit from YYZ because you can't cab back and there is often little difference in timing between airways transit and GO so might as well go with a schedule and less $$. What I don't really understand is why it costs so much to cab to YKF - this and the lack of transit is what really ruins the convenience factor for me.

I'd say that more often than not I don't drive my personal car to YYZ (I don't especially like to pay for parking). The taxi to YYZ is a reasonable option, as is GO for mid-morning departures. Getting back from YYZ is not great.

You are right that YKF is not so convenient to get to without a car. I have biked there (but not to get onto a flight).