[DoughtyOne]

Consider also that the missile that went up did not have to come from a surfaced sub. There may have been one that wasn't surfaced, while the others observed.

[Non-Sequitur]

Again, I'll ask what is the wisdom of such a system? Submarines evade aircraft and helicopters, the don't take them on. For such a missile to work there would have to be some way of targeting it. A simple heat seaking warhead won't work because it has to be aimed in the general direction of the target so it can pick up the heat source. One way or another a sub would have to stick something above the water to acquire the target. If it is a radar mast then the radar radiations automatically give the sub away. If it is something else it still advertises the subs presence and gives it's location away. Launching such a missile gives the subs position away, too, and would be suicide if there are more than one aircraft involved in the hunt.