Actually, you can NPC ships, and you don't need an NPC pilot (yet). But it only works for fighters, some freighters, and speeders (and some ground vehicles?). You have to be assigned as pilot of all of them, and they have to be at the same location. Then you can set them as NPC controlled from the ship inventory (under "manage piloted ships"). It's pretty easy to do, just select the ships you want to NPC, plus the one you're in (you have to be piloting one of them) and scroll all the way down, and there's an option to NPC them in the drop down box. You select the ships by checking the box to the left of their image.
All it does right now is make them follow you. Eventually you'll be able to fire their weapons, etc.