When making online air reservations traveling with my wife, I prefer the window and she the aisle. I select the 'A" seat for me and the 'C" for her. All fine and good. When it comes time to print boarding passes we see that it has been changed to either A&B or B&C. No change of aircraft. I have thought of booking 2 separate reservations but that seems risky should something happen that requires the airline to rebook us. Any thoughts on how to keep our window/aisle seating assignments.