Here is a neat story from CNN of all places about a research team in Hawaii that found the remains of a scuttled Japanese sub from WW2. I am a WW2 history junkie and love stories like this where they find old artifacts, manuscripts or whatever.
Read the story. See what the mission was? The subs carried fold up planes that originally were going to be used to drop insects that were infected with typhus, cholera and bubonic plague on US cities. That mission didn't seem to be working, so they were going to bomb the Panama Canal. The article is unclear whether the sub was captured by US forces or if the Japanese sunk it themselves.
Whenever you are presented with a leftist that is squawking about what a terrible place the US is or how the firebombings of Dresden and Tokyo were crimes against humanity, all you have to do is mention something like this. As a matter of fact, this story ties in quite nicely to my post about the kamikazes below. When you are faced with a brutal, corrupt regime that is your enemy, you must eliminate it or be eliminated yourselves.
As an aside, the article mentions that the anti-aircraft guns were intact. I have to admit that I don't know too much about this particular class of sub, but I do know a thing or two about subs in general. I have never seen one with "anti-aircraft" type of armament. I think the researcher may be trying to describe the deck gun, which was used as an offensive weapon, usually against transports or other lightly armored ships (typically the deck gun was a 4" or 5"). A sub would never get into a shooting match against a destroyer on the surface and subs definitely hated planes. If sighted by a plane, the sub knew that an all out attack by destroyers or destroyer escorts would be imminent so would be more inclined to dive rather than sit there and shoot it out with a plane. Many a sub was damaged by bombs dropped by planes, believe it or not.
UPDATE: You learn something new every day. Trust me, though, not too many aerial battles were fought from sub decks.