I am sure you are already planning on doing just this, but when you get to the airport inquire as to the reason for the switch. Someone will know the answer, but you may have to press the issue as it may not be the TA or GA who does. Oh, and let us know what comes of it.

My repositioning theory just went out the window. Another thought is that perhaps they had a probelm with one of their 777-Bs in the last couple of days and anticipated having it corrected by this morning. I still think there is a rationale explaination for this as there would be no benefit to anybody for the change. The last thing AA wants to do is tick off its elite flyers who uprgaded to F, or those high rev few who may have purchased F.