AC and WS have three flights a day from YVR at reasonable prices so it probably does not make sense for AS to use one of their planes on that route which occupies it for the whole day. It is not like they are growing and with the MAX grounded, that limits things even further. If people are loyal to AS, they will just fly through or from SEA. Canadians would be better off taking a non-stop on a Canadian carrier from YVR.