Originally Posted by
bpauker
It's always been my experience that the baggage policy of the most significant sector of the trip (in this case the AA segment) will prevail, but I thought I'd see if anyone else could confirm a similar situation. Thanks.
You don't mention your origin airport but you do mention starting on AA.
With a U.S. origin or destination the DOT's single-ticket/single allowance checked baggage rules apply. MSC per IATA is one rule that may be applied; there is another. Your AA ticket receipt (designed to comply with U.S. rules) will identify the standard - not the elite-augmented, if any - allowance.