Just spotted on anticipation_09: An Air Canada fare sale. I will be taking the train to Montreal, but if I was not doing so, I'd be very tempted to go ahead and strike a fare now, as it was showing USD179 each way for likely travel dates. (Whoops, just looked again and it's already jumped to USD200 each way). That's before taxes and fees, but still means a flight from SFO would be around USD450, at least $50 less than the equivalent from United, and probably more. This looks like a real bargain.