Air Canada has had a great deal of success with their flight passes in Canada – basically, you buy a book of tickets in advance that are good for flights within a certain area.
The airline has now announced passes that originate in the US. Passes start at about $1650, but go way up from there depending on whether you’re buying a fixed number of tickets or an unlimited pass, and where you can go with the pass. My only issue with these is that there are so many combinations that I have no idea how you choose what to purchase. I would definitely call Air Canada (and your travel agent, if that person knows what they’re doing), to see if this even makes sense for you.