What is the logical maximum practical size for aircraft carriers and battleships?
Short answerCarriers need little more than Ford-class scale without much larger aircraft, and battleships become inefficient beyond something like twelve 18-inch guns or a dense 16.5-inch battery.
NotesCarrier growth follows aircraft and hangar dimensions. Once a ship can operate the required air wing, additional size gives diminishing returns unless aircraft themselves become much larger. Battleships face a different ceiling. Numerous 16.5-inch weapons, or at most twelve 18-inch guns, offer more useful salvos than a few larger pieces. Effective ranging, rate of fire, and hit probability matter more than the largest gun a foundry can produce.