I didn't see a mention of carrier submarines. Will they be included in among the project options?
If so, I suggest adding aircraft module requirements for submarine use. For example, planes launched from submarines must be either equipped with airplane float modules or be designated as kamikazes. Similarly, you should also consider module restriction options, such as not allowing four engine airplane modules on a tiny submarine.
Man the Guns Expanded mod added carrier submarines, but tagging these units as both a carrier and submarine caused them to lose their submarine properties in combat. That's an issue that cannot be addressed in a mod, but rather in the source code. I do hope they're included among special project options.
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