I have contacted them in the past as I was trying to figure out if buying airline tickets or ParkHoppers with airmiles was a better deal - I went with the ParkHoppers at the time, however it looks like I will have enough to also get one of our flights paid for with Airmiles. The tax should be around $140/per airline ticket. I am hoping to book Westjet as they still seem to have availability for the dates/times I want. As SandyinCanada mentioned, I am also planning on booking my "non-airmiles" tickets myself.
Good luck!