• Why was my seat assignment changed?

Contrary to myriad urban legends and FT rants, gate agents do not change seat assignments on a whim for elites, friends, or non-revs. Possible actual reasons for involuntary changes to seat assignments include a change of aircraft for operational reasons and accommodation of Federal Air Marshals, who have specific seating requirements. In addition, it is important to remember that pre-reserved seats are subject to cancellation if the passenger does not check in on time (30 minutes prior to scheduled departure for flights departing U.S. airports; 60 min for flights departing non-U.S. airports) and/or is not present at the gate on time (15 minutes prior to scheduled departure for domestic flights; 30 min for international flights). Finally, if your seat assignment is changed, note that AA does not guarantee to provide any particular seat under its Conditions of Carriage.

FT: Involuntary seat assignment changes (consolidated)