Originally Posted by
gcuk
I think wuileng was asking whether the BA coded flights on the LAX-JFK sectors of the LCA-LAS routing could booked via the AA website rather than calling BA and the answer is yes they can. I have previously booked such flights via AA.com and haven't come across a downside other than losing a few avios when paying with my BA amex card and not getting the enhanced avios multiplyer for BA bookings.
I booked a similar trip with AA and discovered one other downside - it isn't possible to use avios to upgrade one of the transatlantic legs to F even if booked on a BA flight. I guess I should have known this from reading other threads previously but it just didn't occur to me until the Gold line told me. All the other bookings that I had made direct with AA were for US domestic itineraries so the question never arose before.