Originally Posted by SEA1K4EVR

United flies to YYZ also...but you'd have to connect in another city. If you want the Premier miles to count towards your UA status and earn PQD's you need to book the ticket through United (either a ticket on UA or the AC ticket)..it doesn't matter if it's a code share but it has to be a 016 ticket number to get credit. You won't have any chance of an upgrade on AC (not that a Silver has much of a chance on UA)....but if you fly UA with a connection you'd at least have a decent chance at flying in Economy Plus if you fly via ORD, IAD, or EWR. And you'd earn more PQM with a connection vs a nonstop.