Thanks all for the responses.
I was thinking about it today (while at work)
and the thought occurred to me that in RL (or if I take off the training wheels) I should be avoiding aircraft at all costs rather than attempting to dog fight with a submarine, so I will consider just taking that advice and returning my focus to shooting ships.
As for the training mission. The first time I tried that, I had some success (and considerable fun) taking out aircraft. But then I was still running stock. I tried it again a few minutes ago and found that while the planes are not terribly accurate with TMOwTW, they do seem to absorb a lot more bullets. I splashed a couple of Zeros, but had no more luck taking down a sea plane than I did in career mode.