You will need to go to the hobby shop that has the sim, assuming you have permission to do this. Simply locate the Real Flight program folder. Usually you will find this on the C:/ drive in the programs folder. Once you locate the RFG2 program folder, open it and look for the planes folder. This is where all of the planes that are on that system will be. Copy the plane file that you want to a floppy or cd. Take it home and open it up and place the file in your plane folder in your Real Flight program folder. Then open Real Flight as if you were going to play. Go to Select aircraft and scroll to find your new entry.

You can also find some pretty decent plane files on the Real Flight website.

Hope that helps.