I click download, files are downloaded and unzipped, I copy them to my Aircraft folder in FS...
Aircraft don't appear in my FlightSim aircraft directory..
What am I forgetting?
Have you read this?
Also make sure you are placing the downloaded files into the default FS9 Aircraft folder:
C:\Program Files\Microsoft Games\Flight Simulator 9\Aircraft
...also, if the aircraft comes with a gauges folder inside, or a textures folder, or an effects folder, then copy and paste the downloaded files to the main base FS9 counterparts.
Here is a place that has all aircraft distributed as self- installing files.