Having just flown a load of sectors in the US, I think AA have got the boarding process down to a fine art - and more importantly they send people away that are not in the Group they have just called.
That said - on the flight to Paris yesterday the lady was turning folks away that were not Club Europe or Gold - lots of unhappy folks, including queue jumpers but we still got away early on a full flight so it can be done!!
To be honest it was about the only thing BA got right yesterday for me - AA have upped their game significantly, and will get my business if I can give it to them in future!
Aks120