"Normal" planes probably means flyable; these are o.k. but may take up an inordinate amount of computer resources. It's best to use AI specific planes. There's lots of AI planes here at SimViation.
Here's a scrrenshot of the three files required to create AI traffic_new.bgl using Ttools202:
The entries in the aircraft.txt come from the
title=aircraft name in the aircraft.cfg file for each aircraft wanted.
Lee Swordy wrote a comprehensive manual to go with Ttools202 so may I suggest just reading it. That's where I learned how to do it.
Bill
P.S. You can have as many traffic_xx.bgl as wanted and these are placed in your FS9/Scenery/World/Scenery folder by Tttols default settings