My wife and I are flying business with BA and QF RTW starting LHR. We stopover in BOSton and then cross to the west but can only travel with AA. Posters say that AA's business service is pretty poor. Can I upgrade this sector somehow to first - I only have BA miles and am not an AA card holder. Should I contact AA here in the UK, or wait until I am at JFK and see if there is availability and what it will cost?