how bout depending on your rank you can purchase another ship to add to a fleet under your command. fleet ships would be limited on what modules you can add to it but you can add mining modules to have a mining fleet or cargo modules for trading. you would be able to use this new fleet as either an income to help pay for upkeep, or use it as a science vessel for research or scanning for new planets, or use them as an added attack or defense, maybe even set them to help guard planets. you can even add research specifically for fleet ships only.