Always destroy all British and American ships you can with Germany, and only if you desperately want to hit Karelia this turn should it be an exception - and then, only if there’s a chance you’ll keep at least enough land units to hold the territory anyway or you’ll be better off hitting ships anyway. The way I do it: If the French sub survives have hit hit the US transport so it can’t attack Africa or Europe this turn. French fighter always hits the British transport off Canada’s coast (I do this even is the Russian transport goes to back it up, on rare occasions I may include the fighter from Finland-Norway). One fighter against the Med. battleship since I use the battleship and transport to hit Africa or Caucasus depending on the board position, and the odds are good enough for me to take that kind of risk (you will take down the battleship in more than half of all combats, and even though it often costs the fighter it’s better than losing a battleship or the only transport that gives access to Africa, Caucasus and Middle East in my opinion. Remaining fighters should I think join the bomber and, if it somehow survived the Russian turn, the sub in the Baltic Sea.
The transport in the baltic sea I view as flexible in the rare event that, like the sub, it survives the Russian turn. If you can attack Karelia it might be useful to transport 2 infantry with it. Otherwise I’d use it as “Cannon Fodder” agains the Royal Navy just to save planes; the more planes you keep the more you can kill ships again or use them in land attacks, and it would just get killed by the British planes anyway so it’s not useful past the first turn.
If all of this happens it does more than take down ships - it allows you to attack Karelia more easily. Why is that? Because if Britain and the US both cannot attack France you might as well throw all of your land units first turn into Eastern Europe, since Western needs no defense until the next turn. As always you can take the tanks from WE and move them to EE, but more importantly, you can move all infantry from Germany and, if any remain, Italy, to EE instead of having to move them to WE and WE is still easily possible to defend the next turn. I even go so far as to attack the British navy turn 2 or even 3, if I have planes left and they build one up, simply because, even though I’m trading planes for transports, I’m doing more: I’m keeping Britain from doing anything at all to Europe, thereby forcing Russia into a land war with Germany. They should lose this if Japan does its job right. And ALWAYS keep the bomber until last unit. Why? Because if it lands in WE it can hit American transports being built, bomb UK or Russian factories, or be used in European and African attacks in addition to helping with hitting the Royal Navy a second time… forcing the US to reconsider before using a simple build transports/infantry strategy in EUSA.