I booked a reward ticket from ba.com, received an email from British Airways with ticket number and booking reference number. The flight is an American Airline flight. I want to select my seat from aa.com. However, aa.com cannot find my reservation. It seems the booking reference number is not an AA Record locator. The ticket number starts with 125, which cannot be searched in aa.com. I wonder how I could do online check-in if aa.com cannot find my ticket?
Another question, I booked the reward ticket from household account, do all people in the household account satisfy redeem activity (miles don't expire in 36 months)?
I’ll answer the second question first - yes. Since miles are deducted from all accounts, it counts as activity for all of them and sets a new 36 month timer.
As for the first question, mine isn’t an Avios booking but a revenue one involving AA flights… when I go into Manage My Booking on BA.com, and click to select seat assignments, BA.com asks my permission to transmit data to AA.com, which then opens the seating interface on AA.com with data already there and ability to select seat. You can also see the AA record locator number on that screen.
Note that you MAY need to re-enter all your API (Passport, Known Traveller Number, etc.) on AA.com, as this data was not transferred over from BA to AA for me.