Originally Posted by bocastephen

All international inbound flights, except those with pre-clearance, must clear immigration and customs at their first US port of entry, then pick up any checked bags, re-check the bags onwards and then clear security again before their next flight.

JAL should be able to check the bags through so they just need to be picked up at ORD baggage claim and taken to the AA bag transfer desk to be dropped off again. If they’re tagged through there won’t be a fee.