Upgrading on AA-operated flights sold & marketed by BA
This is perhaps a novice question, but does anyone know if you can upgrade w/AAdvantage miles (and copay, of course) on an American-operated fight if the ticket was sold by British Airways?
A sample itinerary would be LIS-PHL-DCA on leg 1 and IAD-LHR-AMS on leg 2. The ticket was sold via BA, but leg 1 is entirely operated by AA. So, my question is whether it's possible to use AA miles to upgrade on the AA-operated leg? Or, is that not possible since the entire ticket was issued by BA.