the RN Andrea Doria was able to carry the Macchi m18 flying boat on its catapult. Is not currently modeled.
Unfortunately it seems Gaijin completely moved their priorities from props, so I doubt we will see such seaplanes anytime soon, for Italy this is especially sad since it wasn’t added from the start of the game to get as many interwar/WW2 planes as some other nations, despite a ton of options.