Originally Posted by
wesport
I booked an American Airlines flight via British Airways with avios. I then went to finnair and moved the booking to my AA account. When it comes time to check in, do I do it on AA or BA?
The Operating Carrier takes care of the checkin. I know that some airline websites are smart and forwards you to the operating carrier's checkin portal. If AA is operating the first segment of your flight you would checkin with AA and they may or may not allow you to checkin online or if they do they may not allow you to print out your boarding passes and it will spit out a "Airport Checkin Required See Agent page" as they will need to verify your travel documents!
If AA were operating only the Domestic portion you would be checked in for the Domestic portion but the international portion would need the agent to verify the checkin documents as well.