We have talked about allowing corps to own planets, it's a possibility but we haven't really figured out how we would implement it in a fair and balanced way yet.

Corporations can currently build military fleets, and there is a specific type of corp - a "security force" - which basically is a private military corporation, though we're looking for more ways to make the different types of corporations more differentiated in the future.

Corporations trying to leave your empire and become a proper megacorp is also another idea we're looking at!