Originally Posted by
FAA1996
The last flight (BA operated by AA) is the one that I couldn't pick seats for on aa.com, so I logged into ba.com and it took me back to aa.com at the click of a button. This let me choose my seat for that flight but created a third record locator.
The fact that you were taken from ba.com to aa.com for the BA code-share on AA did not create the third PNR - it was created by AA for its operated flight the minute you booked the flights. All carriers create a separate PNR for their flights booked under their partners' code-share flight numbers. The PNR where you have your 2 prime AA flights (those booked as AA and operated by AA) will not contain information about the AA operated flight booked as BA (it will list it as the BA*AA flight).
Since you have 6 flights in your itinerary there are 2 ticket numbers (conjunction tickets) because it is only possible to have 4 segments on one ticket.