yes confusing indeed. When I flew last it says operated by Air Nostrum but flew Iberia and all was handle by Iberia except the plane was Nostrum.
So the trend now would be that, in your case it seems the opposite, as the operated by is USAirways and the plane is AA!!!reason said should be the plane of USAirways and the ticketing is done by AA.
welcome to flying today it is not what it used to be. One reason not in aviation even if my majors is ::)