I agree with Spartan about Germany’s priorities.
Germany’s main priority is to take Moscow. This may not be feasible, so it is acceptable that they severely weaken Moscow for a Japanese overthrow. Those planes do little to help this, they are instead a (possibly major) hindrance to allied shipping. That is a tertiary priority. The secondary priority is to take and hold Africa. So this strategy, tho not broken, is absolutely not optimal.
I also make a huge tank build on G1 if Russia gets bad dice. You wont have a lot of time to take advantage before Russia starts pumping out more inf and starts getting her first reinforcements, so dash dash dash! Its ok if you lose some armor, Germany needs to expand fast to help make up the money and put the heat on Moscow. This should really help the Japs make a solid push at least up to Novo in the early part of the game.
With Russia on full defensive, Germany has plenty of time to build troops for the Fatherland, really with an income over 40+, it only takes 2 turns to get enough men to protect the core countries for a long time. And if you are stacking up Karelia (with enough tanks its totally feasible), then you are probably holding Norway and as well you are using your main objective tools to simultaneously achieve your 3rd objective, stopping allied reinforcements.
That’s a lot more optimal.
That said, in a more normal game I do like to beef up the German airforce, albeit more slowly. A bomber G1, a fig here and there afterwards. Suddenly only having one BB to protect those 3 trannies when UK is thinking of snagging Norway in R3 or so is not looking like a smart move at all.
As for Japan, I always save 1 ipc from the axis bid for them. 2 trannies and an IC is just too good of a start. Yes “technically” its not optimal when you consider the boats are cheaper and move tanks just as easily, but the point is having an early and advanced front. The change in the power dynamic is maybe hard to measure quantitatively, but it is definitely worth it. Then I build a trannie a turn until I am up to about four or five or so, depending on what exactly I am doing. Tho if the allies made some big KJF moves and got real good dice, I might hold off on that IC purchase until Im sure I can hold it…