1 - Unable to walk around in a CV while it's moving. (This prevents all sorts of cool interactions. Imagine AI ships that spawn units when you attempt to board them. Or other players docking a ship in an attempt to take it over, etc) 2 - NPC races do not expand territory, rebuild, or etc. 3 - You cannot take offline friends with you, the Mod EmpyrionPassenger from ASTIC does what Vanilla should be in the game to take friends with you on the trip.