Xerxes-class battleship

Nothing else flying is bigger than a Xerxes-class battleship. At exactly five hundred meters it edges out the Martian Donnager-class by a little over twenty-four, which is the whole point: the United Nations Navy holds that bigger is strictly better. It is the third redesign of the same basic capital ship, named for a Persian king in keeping with the fleet's habit, and the navy has stayed comfortable with the design for decades. Eight enormous Epstein drives push it. Two side-mounted railgun turrets, a point defense network and twenty-four rapid-reload torpedo bays arm it, and its hangars hold Phantom-class escorts, Marauder-type dropship skiffs and shuttles enough to put out a small fleet of their own. It also fights close, using grapplers to latch onto a target and send boarding parties across, and it wears the thickest hull plating in service for the times that goes badly.