Westjet (WS) is closely patterned after Southwest (WN). Fine airline operating very new 737-700s on that particular route. Don't expect much in the way of food/drink (other than very basic snacks) or entertainment (none), not that AC is much better.
Other possibilities are Jetsgo and HMY Airways (latter claims to offer above average/superior food/beverages & IFE).
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by wideman:
However, because Canada decided to put most of their cities on/near the U.S. border, you have some other options. </font>
Just be aware that the Seattle option can be expensive. Car rental rates in Seattle are generally not cheap and various taxes and fees (some of it to fund a billionaire's football stadium) add 28% to the pre-tax rate. A r/t bus trip will cost you USD 55. That'll eat up most of the savings and we haven't even gotten to the cost of getting to BUF.