Not me, but family who cannot shrink baggage down to the hand luggage only
Trip is ticketed with BA, but using AA for OKC to DFW leg, then BA A380 onward to LHR

Question is this, luggage in hold on OKC to DFW leg is this automatically tagged through to LHR, and no need for passenger to do anything with it while changing between terminals for the Dallas connection (have told them to follow signs for the air train, and should be a Terminal A to Terminal D change).

On the reverse trip, I know they will have to pick up their luggage and walk it past the US customs desk before dropping it.

Thanks in advance