Here is a link to my website that has a more in-depth and up to date tutorial on how to install addon aircraft. http://fstipsandaddons.com/tutorials/installing_aircraft.html
There is also one for scenery here: http://fstipsandaddons.com/tutorials/installing_scenery.html
And repaints: http://fstipsandaddons.com/tutorials/installing_repaints.html
Here is something I made that shows how to install addons for FSX. I hope it helps.
(I have windows XP, this might be different for Vista or 7- location of were to put the folders and files.)
How to install addon aircraft.
1. Make a folder somewhere in your computer where you can store your addon aircraft. (I called mine FSX Downloads). You can store your addons here in the zipped file format in case the one you unzip and use in the game gets messed up or deleted.
2. When downloading the addon aircraft, save the file to that folder or move it there when it's done downloading.
3. Extract the folder and go inside it. Make sure all the main parts of the plane (model, panel, texture, sound, and other files) are located right inside when you click on the folder. If you have to click through a couple of folders to get to these, move them up to the top folder.
4. Copy the aircraft folder to: C:\Program Files\Microsoft Games\Microsoft Flight Simulator X\SimObjects\Airplanes
NOTE: Even if the addon is a helicopter, still put it in the airplanes folder, not the rotorcraft folder.
5. Go into the downloaded aircraft folder and look to see if there are any folders called gauges or effects. If there is, see below.
Effects: copy all the effects in the folder (not the folder itself) and put them in:
C:\Program Files\Microsoft Games\Microsoft Flight Simulator X\Effects
Gauges: Same thing as above, except put them in the gauges folder.
If it says a copy of it already exists, say yes to all to overwrite them.
6.If there any any extra files or folders (pictures,read me,manuals,ect) delete them unless you want to save them. Then FSX won't have to load any extra stuff when you want to select a aircraft
7. Exit out of the folders and your done!
How to install Addon Textures. (or repaints)
1. Make a folder somewhere in your computer where you can store your addon textures in the zipped file format in case the one you unzip and use in the game gets messed up or deleted.
2. Download and put the texture folder in the folder you just created.
3. Extracted the folder and then put it in the folder of the plane it's for.
C:\Program Files\Microsoft Games\Microsoft Flight Simulator X\SimObjects\Airplanes
FSX Helicopters. (any addon helicopters should be put in the aircraft folder)
C:\Program Files\Microsoft Games\Microsoft Flight Simulator X\SimObjects\Rotorcraft
4. The name of the folder that is actual going to be used for the textures is going to be called something like texture.(something). Make sure you only have to click on the folder to see all the texture files. The files are ussually .dds or .bmp.
Now open up the aircraft.cfg file for the aircraft your installing the textures for. You will see a bunch of entries that look like this:
This one is for the boeing 737, depending on the airplane, some parts of this will be different.
title=Boeing 737-800 Paint1
description="One should hardly be surprised that...."
Each one of these is for a different texture or paint for the aircraft.The addon texture your installing ussually has a readme in it. Open that up and look for something like what was shown above. Copy that and put at after the last fltsim entry. NOTE: make sure the number after fltsim is the number right after the last entry. ex. If the last entry was called fltsim.7, you would put fltsim.8. Also, make sure what is to the right of texture= is the same name as the folder (without the texture.). If the name of the folder was texture.swair, then in the aircraf.cfg file it would be texture=swair.[url][/url]