Canada - YYC "improvement" Fees - what are the rules?

Hello,

Looking for nicely priced WestJet flights, I see that the fees can vary even if the route is the same.

WestJet has, of course, a lot of routes with connections in YYC. Sometimes, the tickets come with no YYC related fees or taxes, sometimes they do.

For example a flight from SFO to YVR via YYC can have only US taxes, or have added to that a "Canadian airport improvement fee" of 25.20 and "Canadian goods and services tax" of 1.30. Thus, the flight becomes more expensive by 26.50$.

The first connecting flight is usually sans fees & taxes, any later connection becomes more expensive, as if they constitued a stopover. I had always though that connetions within 24 hours are deemed connections and not stopovers.

Does YYC have special rules there? Or is that the same Canada-wide? What's the deal?

There are more weird things going on with the "airport improvement fees". YHZ->YXX with three stops (no connections) has 20$, which is the usual YHZ fee. When connecting once, in YYC, it can stay at 20$ or rise to 45$. With connections in YYZ and YYC, it becomes 24$. With connections in YYZ and YEG it can be 24$ or 45$. Then again, with connections in YHM and YYC it stays at 20$.

?

From http://www.yyc.com/Default.aspx?cid=236&lang=1


"The fee does not apply to passengers connecting through Calgary International Airport, nor are fees required for children under the age of two travelling for free on their flight.
Connecting passengers who are exempt from the Airport Improvement Fee (AIF) are those whose scheduled departure time from Calgary is:
• Less than 24 hours from the scheduled arrival time of their international flight or;
• Less than four hours from the scheduled arrival time of their domestic or USA originating flight.


A ‘connecting' passenger is defined as less than four hours scheduled ground time between domestic and/or U.S. arrivals and domestic or U.S. departures, and less than 24 hours scheduled ground time between a domestic or U.S. arrival and an overseas departure."

Ah, they distinguish between origins/destinations.

Is that common among North American airports?

And what is the reason behind this? Wouldn't a passenger who stays more than 4 hours spend more money at the airport than a passenger who stays less than 4 hours?