The galaxy seeds itself based around what planet you pick. So when you're looking at the initial setup, there are no AI worlds yet, technically. They appear once you've selected your starting planet(s) and are usually as far away from the human world as possible. The planets without ships at them will still give you a starting bonus ship if you select them as your homeworld, but it will be randomly selected. Everyone always starts with bombers, frigates, fighters, and one extra ship type. You can select multiple starting planets also, but if you lose any of them you lose the whole game, so it's not as much of an advantage as you'd think.