Hello all! As someone who loves the more unique ships of WW2, the I-400 class submarine has always been one of my favorite ships in history, and was the largest submarine in the world prior to nuclear capable subs! In game as far as I am aware the sub can carries scout planes.
In real life however, the sub was able to carry three Aichi M6A Seiran floatplane attack aircraft in its water tight hangar. The sub was designed to surface, and launch the aircraft to surprise attack strategic targets such as the Panama Canal.
I don't have the I-400 unlocked yet, but I think it would be neat to give it a flight deck upgrade option to allow it to deploy a single squadron of either a 1x scout, or 3x dive bombers and/or torpedo bombers. I don't know how effective this would be as far as game balance is concerned, but I wouldn't think it would be game breaking as a squadron of 3 is likely to get shot down easily and not do too much damage. Also the total number of aircraft could be extremely limited, so once the 3x bombers are dead, you don't have any more to launch.
I don't know how challenging this would be to add, but it would add a unique and historically accurate feature to what I consider an icon of naval history! I would love to see this happen! Happy hunting!