I THINK the AI traffic total is limited by your machine's ability to track and handle computations all the traffic within 40 nm of your plane. I think that is the"range" that the AI "exist" within. Outside of that range (or something like that) your computer does not bother keepong active trrack of them no matter how many flights are "technically happening".
One real limit is you machine's abilty to cope with all the computations needed for thos close planes and keeping the framerates "flayable".

There might be some other coding limit... but getting the "working radius" traffic overlaoded would require really loading up flight plans out of and into one or two close airports.
Interesting experiment though.
best,
.....................john

Intel i7 960 quad 3.2G LGA 1366, Asus P6X58D Premium, 750W Corsair, 6 gig 1600 DDR3, Spinpoint 1TB 720