Correct me if Im wrong, but if the aircraft isnt loaded asymetrically, then there should be no reason an aircraft should favor one side heavy. To me, that would indicate improper maintenance procedures, and the ailerons would have to be readjusted on the ground. The only time that should apply is when the aircraft is prop driven, and the airframe should pull in the opposite direction of torque...and that really would only apply to prop aircraft that are both single engine, or dual opposed engines that cant synchronize engine rpm.