AI traffic is the computer controlled traffic flying around you in the simulator.
 Freeware packages
For beginners it's recommended to use World Of AI's freeware packages.
- Link to World Of AI
 Manual installation
It's possible to manually install your own AI traffic. It can be time consuming but for some it's the only solution as you can stay updated with models and flightplans.
 Freeware AI aircraft models
Theres a host of freeware models out there. It is best to use the most common models as they are easier to find and more repaints exist.
A list of the best and most used AI models can be found here: AI aircraft models