Map size question


I posted this question a few days ago (or meant to) but I can’t find the thread - so maybe I spaced and minimized the page before posting.
Anyoo - apologies if this is a double post.

I’m in the early stages of developing a flight sim, and we’re looking for an appropriate game engine.
Because of the nature of a flight sim, it requires a larger map than a normal game.

I’m wondering of AI Actors, other planes, ships etc can exist and be going about their business beyond the player (10k) map limitation?
The area I need depicted is 500 x 500 miles or so, and mostly ocean with some islands. I know I can stream map grids, but it’s AI activity
(that the player will later encounter) that I’m worried about. I need the map “alive” as it were to create an immersive experience.

I’m trying to get a handle on whether we can make this engine work, or if it’s a dead end.
Any help appreciated.

I’m interested in this Q also. I hope someone gives you some insight.

I’m interested to get some answers for this as well. Particularly for online games.