SOS - anyone with any experience of connecting from a BA flight from LHR to a AA domestic flight.

Am looking for a comparison between connecting at DFW, ORD, LAX.

Do all of these involve terminal changes? How long does this take?

Where terminal changes are involved, do they all have bag check-in areas in the arriving terminal straight after customs?

How much time should you allow for a BA-AA connection at each of these airports?