kEiThZ
Superstar
This is an interesting point, and one that I hadn't actually thought about much when this topic has been brought up occasionally at the water cooler, etc. I guess smaller planes still take up a landing and take-off movement regardless of how many passengers they carry, just like a subway train the overall passenger capacity at the airport depends on the size and capacity of the aircraft. I remember hearing Buttonville (which is slated to close) is in the top ten busiest airports in Canada based on aircraft movements. I guess once it shuts down those aircraft will need to go somewhere.
It's even worse than that. Thanks to wake turbulence rules, you have to be careful how you slot aircraft. Can't slot a smaller aircraft too close to a heavy aircraft or you'll have an accident on your hands. This means that heavies actual take up more "slots" than what you would think they take up.