I have a question regarding FSX aircraft.Lets say you own a payware airliner, which is designed out of the box for passengers.Now you want to convert this aircraft to a cargo carrier, whether or not this exists in reallife.1. Could this be done by editing the aircraft cfg files?2. How about changes to the flight model?

Are the flight characteristics THAT different between the passenger and cargo versions?If not, the difference is the loadout - station loads and weights. You can change that in the aircraft selection dialog.However, if the cargo version can handle a higher gross weight, etc., then you would change the corresponding sections in the aircraft.cfg file. You should NOT have to touch the air dynamics file at all.