At Halifax Airport, Nova Scotia, and likely at other Park 'N Fly locations, Westjet passengers get a 25% discount at checkout. Just show your boarding pass and they apply it at the gate. I always printed off a discount coupon from their web site, amounting to about 5% discount. Last time the shuttle bus driver alerted me to the Westjet discount. Their web site says a 20% discount buy the cashier said no, it's 25%. Not to be missed. No expiration, best I am aware.