I had purchased several of the Western Canada flight passes in the past. Unfortunately they no longer exist (have not been available for a few years now). You'll need to have a look at the current flight pass options to see what best suits your needs.

I'm not sure why it went away. Maybe AC thought it was too good of a deal for people on certain routes so replaced it with the more convoluted system of commuter, regional, inter-regional, etc. passes.