A simple clarification as people are often confused (which is fair enough - why should they know).

There are multiple (but 4 main ones) historic airline booking systems (called GDS's Global Distribution Systems) - which used to be owned by airlines. But each airline has one they use in-house (this gives you an idea, but is out of date) - http://en.wikipedia.org/wiki/Compute...vations_system

When you make a booking, the airline creates a PNR (Passenger Name Record) on that GDS - this is 6 Alphanumeric Characters i.e. ..2B3C that is unique to that GDS (and you might use to see on ViewTrip or the GDS equivilent).

The trouble is that if you make a booking that includes multiple airlines, it will be on the system the the airline you book with uses (AA's system in your case) - but not on the other airlines systems, so they might struggle to make changes to their sectors.

Therefore every airline generates an 'Airline Locator' which is also normally 6 Alphanumeric Characters (some exceptions, notably MH who only use 5 in their locators).

So you should have Multiple Airline Locators in your booking as you have multiple airlines. And you'll have an AA one, even if no AA sectors. If this booking includes say, an Iberian Codeshare on BA, you'll have an IB Locator as well. You will have myriads of (largely one world) 'Airline Locators' - but you should only have one for BA. (You may have others that relate to BA Sectors - i.e if a US codeshare on a BA flight - but you should only have 1 for BA).

Can't help feeling I write the above more succintly, but hope it helps. The biggest confusion is between the 'PNR' and the 'Airline Locator' which are two different things.