Things You'll Need
Instructions
Find an aircraft you would like to add to your simulator. There are many sites on the net, where freeware planes are available. Be sure that the aircraft you download is compatible with your version of Flight Simulator.
Extract the compressed file to your hard drive.
Review the file contents. In some cases, and installation applet is included, and all you need to do is run it. In other cases, you must install the file manually. Usually there is a "readme" file that explains the installation procedure. If manual installation is necessary, then continue below.
Read the instruction file of the aircraft you downloaded. Usually, all the files will already be arranged within a single folder carrying the aircraft's name. This folder will contain several sub-folders that are already arranged as they should be. However, occasionally, an aircraft with unusual features may require other steps.
Drag and drop the folder with the aircraft's name into the "Aircraft" folder in the main directory of your Flight Simulator installation.
Run Flight Simulator, and verify that the aircraft shows up in the list of installed planes. If it does not, then you did something wrong. Recheck the readme file, and try again. You probably missed a step, or placed a file in the wrong folder. If this does not work, consult a major flight forum on the Internet for additional advice.