What is supremely annoying is when the "through flight" includes a plane change, and in the case of DFW, a terminal change. Last month I took a flight from SJC to IND with a stop in DFW. Although I was able to upgrade the entire flight, it included a plane and terminal change in DFW. It is beyond me why AA lists this as a through flight to me - it's almost impossible to get to the other gate in time to board with FC and get carry-ons stowed!