http://www.reportonbusiness.com/serv.../Business/home
I just did a quick search on westjet.com and aircanada.com for a flight I have to take to Toronto in July. Everything else being equal, Air Canada's fare was $125 more than WestJet's.
So if you have some travel planned over the next few months, it might be a good idea to book on WestJet quickly before they add on these charges.