Dropships modified to fit the formations various successor states actually used. Like the Capellan augmented lance for example. There should be, for instance, a Capellan Union that pulls four mech bays for two vehicle bays and the balance in cargo, but I don't think there is. I'm also puzzled that Tomori Trans Industrial is making Vengeances with 40 bays for a nation that uses 36 fighter wings and not a version with fewer bays and more cargo. You don't need bays for spare aircraft, you move them out of cargo into the bays left empty by lost aircraft.