Originally Posted by flatlander

There are people on the AA forum who can armchair-lawyer this better than I (if you wish to engage with them...). However, have you checked the ticket receipt you got when you booked?

US DOT Regulation 399.87 is relevant:

"For passengers whose ultimate ticketed origin or destination is a U.S. point, U.S. and foreign carriers must apply the baggage allowances and fees that apply at the beginning of a passenger's itinerary throughout his or her entire itinerary. In the case of code-share flights that form part of an itinerary whose ultimate ticketed origin or destination is a U.S. point, U.S. and foreign carriers must apply the baggage allowances and fees of the marketing carrier throughout the itinerary to the extent that they differ from those of any operating carrier."

There are some other US regulations which, I think, require the allowance to be printed on the ticket (or written into the ticket receipt for an e-ticket).

So you should be getting the BA Club allowance the whole way, as experienced in the previous post, and I think you should have been told that somewhere in the ticket confirmation that you were issued.