Originally Posted by
ijgordon
I really think it's silly to transit another country instead of taking a nonstop because you're bored with what is a very good product. JMHO of course. Pretty sure you have to clear Canadian customs in YYZ, though I think the AC terminal (T3) has some sort of expedited path for Int'l-to-Int'l connections. You may even have to collect your checked baggage. More info in the Toronto forum. Not sure about YUL, doubt it's any easier.
If he is going to fly AC, he gets one of those nifty pink "fast-track" customs passes. I've had 2+ hour waits to clear customs in LHR after flying CO. The trip to Canada is worth it for that alone, IMO.
(And FWIW, I will only fly CO to LHR if its the 9am flight for that very reason. Doing it on Monday, actually)