Pacific:
Having a US stack sitting on [whatever money island], or keeping Malaya a haven for the Allies (and therefore +8 IPCs for UK/ANZAC), or defending an advancing Chinese stack…
I don’t think that’s going to hurt Japan enough–not like forcing Japan to heavily invest in fleet, and then killing most/all of it, would. Without a big-and-still-growing American navy to pay attention to, Japan can afford to do two things at once. The American fighters can only be in one place at one time, because without them in a single-stack form, they’re not strong enough, until at least US 6 or so, to withstand a direct hit by the Japanese.
They are also not strong enough to directly strike the Japanese navy. Perhaps adding a few tactical bombers in addition to the one the US starts with into the mix would help that.
It sounds to me like in the Pacific what would result is a grand maneuvering game that, Japan, since it’s in its home turf and has a material advantage, will still come out on top of. Meanwhile in the Atlantic, Germany should either have shut down Russia and dug in for the long game (where Germany’s power is steadily increasing), or already have outright taken Moscow and an Axis victory may be 1-6 rounds away, depending on the status of Egypt.
Atlantic:
What if you did this in the Atlantic for a few rounds? Assuming the British helping you with some air bases (more on that below), you could get some fighters in Moscow. Okay, you’ve held Moscow, hopefully… I say hopefully because that likely requires an early Japan DoW to safely and consistently make it (more on that below). Germany does the normal push there, gets locked out right in front of it, but now there’s reduced American pressure in the Atlantic on Italy, or even Germany directly. Germany lets Moscow stand (indeed, because Germany absolutely could not take it with such heavy US air investment). They dig in for the long game, and try to push south into the middle east. Yeah, your fighter stack can fly around and put up road blocks in the Caucuses/Iraq, or in China, or whatever else, but Germany is still making more money than is comfortable during this period, not to mention you’d be sending 2-3 turns of plane production (10-17 (+ starting planes?)) to Europe before your attention would need to return to the Pacific to contain the monster that Japan has become in your absence.
The biggest shortcoming is that those fighters are fantastic for defense, but they don’t allow you to push back against the Axis very well. Britain excels in this defense-centric role, especially in Moscow. However, the US usually needs to be the one actively pushing against the allies. I don’t know if a fighter stack would accomplish this.
Routes fighters can take to Moscow:
Northern route:
US: US -> Gibraltar/Nova Scotia
UK: Air base on Gibraltar/Nova Scotia
US: Gibraltar/Nova Scotia -> Scotland
US: Scotland -> Northern Russia (Nenetsia, Archangel, Novgorod)
US: Northern Russia -> Moscow
Takes four turns and one new UK air base to make it work. If The axis have Gibraltar, no problem, you can go through Nova Scotia, but for reasons I think are clear to most of you, Gibraltar is strictly better, especially better to have an air base on for the allies. Nova Scotia is also somewhat useful because planes can reach it from the Western US in case you built there and then changed your mind or wanted to feign directions.
A G6 Moscow hit can happen. To get there in time requires a J1 or J2 DoW.
G7 Moscow hits are more likely in my experience, which means you’d need a J3 DoW.
If the British/Russians alone can hold Moscow on their own through G7, which is possible but not something that is by any means a certainty, then, and only then, can you get there with your planes without an early Japanese DoW. However, by this point, landing in Nenetsia may not be “safe” without a bit of planning with Russia. The Germans will have had all the time they need to have some tanks/mechs in range to snake up north with their own air force and devastate your plane stack before it arrives in Moscow. If you are “lucky” and get a J1 DoW, you can bring your planes in piecemeal, but this greatly increases their exposure to a German strike.
Other bad news: US planes flying this route are essentially useless apart from their potential one turn stay on Gibraltar.
Southern Route:
US: Eastern US (only) -> Gibraltar
UK : Air base on Gibraltar
US: Gibraltar -> Cyprus
UK: Air base on Cyprus
US: Cyprus -> Moscow
You can always make it in time to stop a G7 Moscow, but to be there for G6 requires an early Japanese DoW.
This is an entire turn shorter, but utterly depends upon Italy not taking Cyprus (or Britain retaking it if they do). It also costs Britain 30 IPCs in air bases. Germany/Italy could attempt to bomb the air bases before the US’s turn, but with the fat stack of fighters sitting there, you probably want them to try this.
Planes in this scenario are also useful for the entire flight. Depending on where planes are coming from, it’s usually only a one turn delay to hit SZ 97 or 98, though 98 requires a safe landing zone in Malta (which is probably 100% okay), or Northern Africa somewhere.
edit-
Then there’s the scenario where you go Western US -> Soviet Far East -> etc. This requires that some Russians stay behind in the far east to help you out, else it’s exceedingly simple to have Japan delay you by 1 or 2 turns, which is damning. The Russians also can’t as easily afford to plop down air bases for you as the UK can, but an air base in the Soviet Far east puts you in Moscow in 3 turns with a hop over Yenisey and is likely worth the 15 IPC investment if you can get two or more turns of fighters through it. But, it’s potentially easy for Japan to take the Soviet Far East on J2, even if you drop some planes there. It would require some navy backup. I am out of time or I’d explore this a bit more.
It is of course possible to use a combination of any of the above at the same time, if that’s better for some reason, though fighter stacks get exponentially more juicy to hit the smaller that they are.
There are also like ten different 4-turn routes across the Med to Moscow, and they’re all useful for different situations.
If you want to try a game like this, Nippon, I’ll play the axis against it. You can decide what turn you want Japan to declare war on you (I default to J1 in 95% of cases, and 100% of the time when I’m playing 1v1).