Originally Posted by
stevenshev
No. And AA will only endorse it if it's an endorsable (read: full fare) ticket.
This is not entirely true. If the AA segment is plated on UA stock (016), then UA can accept the ticket without its being endorsed first. If this is an international ticket, this may very well be the case, as the standard is to plate the ticket on the carrier who carries the passenger on the first overwater segment.