Originally Posted by
OxonCantab
This is a very knowledgable response. However, I was able to pick a seat, and view a seat map last month on a flight booked under the exact same circumstances.
I guess you were lucky (simple as that
). You should get an error message when you try to select a seat (which, I believe, you do now). BA creates such PNRs for its own operating purposes and all actions with your booking should be initiated by AA and done in its PNR.
It's strange that the other way (BA coded AA operated flight) it works much easier and BA agents can select a seat in the BA PNR. And even if one wants to do it themselves on aa.com, the AA PNR will be fully functionable...