Moderator: American AAdvantage
Join Date: May 2000
Location: NorCal - SMF area
Programs: AA LT Plat; HH LT Diamond, Maître-plongeur des Muccis
Posts: 62,946
Because you are on two oneworld tickets, BA will probably be able to check your baggage through.
Regardless, on arrival at LAX you will have to process immigration, collect your baggage at the indicated carousel, process customs - and recheck your baggage at the counters just as you exit customs. If you are arriving internationally and flying onward to a US domestic destination, you are required to process formalities at your USA port of entry (unless you're arriving from DUB or one of the few airports you pre-clear for the USA by processing formalities prior to departure).
You will then have to process security to get airside at the Tom Bradley International Terminal one level up and walk the airside connector to AA terminal 4 (unless it's one of the occasional flights that departs the TBIT), or out the TBIT door walk on the kerb to your right to Terminal 4, proceed one level to departures, process security and depart.