The 1930 treaty concentrated on cruisers, destroyers, and submarines without significantly reshaping the carrier rules inherited from Washington. Several navies already operated fleet carriers or seaplane carriers, so aviation was not being dismissed as harmless. The survey names Courageous, Glorious, Furious, Hermes, Eagle, and Argus, the seaplane carrier Albatross, and France's Béarn and Commandant Teste alongside American and Japanese carrier forces. The uncertainty lay in what those ships and their aircraft would become as operational systems. Different states were experimenting from distinct starting points and had not yet converged on a common carrier doctrine. Keeping carriers away from the centre of negotiation preserved development freedom before international limits could harden around an unsettled design.
Chapter · 39:42-42:03
Why aircraft carriers stayed outside the debate
Carrier aviation was advancing in 1930, but the treaty mostly repeated Washington rules because no navy yet wanted close limits on an unsettled field.