FS9

For FS9, the most widely used model set is World of AI (WoAI).

You can find a World of AI Installer App at the VATSIM forums, just follow this link.

swift and FS9 can use fully flyable aircraft to render other online pilots, they will work nicely.

Install all AI aircraft into the \aircraft\ directory of your copy of Flight Simulator 2004 / FS9.