I've been on flights where they've actually held the plane a few minutes past scheduled departure time to accomodate connecting pax from another AA flight. Of course that was an international flight so perhaps if baggage had already been loaded it was either hold the plane or spend even more time offloading checked bags. Another factor might have been the number of pax involved. Are there any general criteria AA goes by to hold a plane for pax running late? If it's last flight of day and customer misconnects through no fault of their own, does AA pay for hotel?