mjriches, there may still be something with American Airlines. If you go through the seasons since seven, many first leg flights still have an American Airlines flight involved.
And this is speculative, it also explains why some potential start cities haven't been used because American does not have a large international flight presence in those cities; e.g., Atlanta (the HQ for Delta), and Minneapolis-St. Paul (now a second hub for Delta after a merger a couple of years ago.)