You need to go into My Computer, then Microsoft Games, Then FS2002/2004 (which ever one you have). In there you should find a folder called, Aircraft. Open that folder and find the file/aircraft you want to make changes to. Once you've found the file you want, open it and in there should be a CFG document called aircraft. That's the one you want
That's the file which contains most of the controls of the aircraft. You can edit those, but I'd advice you not to mess with them unless you're fully sure you know what you're doing.
Hope that helps
[Edited 2004-11-24 23:15:32]