In this day and age of codeshare flights, my question is this: if you look in any OAG and see a codeshare flight listed, it is shown twice...once for the carrier actually flying the route, and again for the codeshare carrier. The departure and arrival times are obviously the same, but in many cases the aircraft type is not. Why is this? I see many instances where the carrier flying the run is shown as a 747, but the codeshare carrier is shown as a 747-400. Why is there such an obviously contradictory thing like that?