Dreadnoughts are one of the most powerful warship classifications, being outranked only by the extremely rare mothership class and possibly the "supercarrier". They are much bigger than even battleships, allowing for even more weapons, even stronger armor, and even more shield layers. Even with all this added weight, dreadnought-class ships are almost always outfitted with extremely powerful engines, allowing them to keep pace with the much lighter battleship class. When present in battle, dreadnoughts are always the flagship of their fleet, and they almost always carry a few fighter bays. Being one of the most powerful ships, they are also one of the most expensive to build; militaries only have a few dreadnought-class ships if any, and they are rarely seen in battle, usually being saved for dire occasions.