While your comments are absolutely correct, my point remains that they could have accelerated their shift to a total war production footing years before they did. The UK’s a/c production went from 8000 in 1939 to 15,000 in 1940 and to 20,000 in 1941, while Germany went from 8300 in 1939 to 10,800 in 1940 to 12,400 in 1941. The point isn’t the specific numbers, the point is that Germany didn’t put the pedal to the metal until 1943. By 1944, the UK had only managed to grow their aircraft production to 26,500, a 33% increase over 41, while Germany went up to 40,000. Even if we reduce that to 30,000 to account for the shift to single-engine fighters, that still represents about a 140% increase in the same time period. If they had the right policies and personalities in place, they could have been outproducing the British in 1940 and 1941.
While your comments about oil production and pilot training are also true, they are not really relevant to my simple point that German industry could have produced more, earlier in the war, if they had chosen to do so. The OP was asking for possible scenarios that could have lead to an axis victory. A more productive Germany earlier in the war is something that is certainly within the realm of conceivable possibility. If that contributes to a possible scenario in which Germany knocks Great Britain out of the war in 1940, the question of oil shortages would not yet have come to a head during that period.
Regarding the comments on the Repulse, etc., in my hypothetical I specifically mentioned the need for longer-range aircraft with the Me-109s range in mind. There is no technical reason why the Germans could not have had fighter aircraft with a range similar to the Zero in 1940; the Japanese did it. A 600-mile combat range would pretty much cover all of the water around the U.K from continental Europe and Norway. Again postulating the foresight to build and train a land-based naval air arm (I’m thinking of aircraft equivalent to Nells and Bettys and Zeroes), there is no reason to think they would not have some successes against the Royal Navy. In 1940, (and I 'm sure you know this), naval ships did not have the AA firepower and fire control that they had in 1944, and while land-based fighter cover would cause some losses, coordination was still subject to failure (the Repulse and PoW were supposed to have fighter cover that day) and even if air cover was present some of the bombers would get through.
A strategic bombing force is expensive, but this goes back to shifting away from consumer production earlier in the war. That is a large part of what would need to be sacrificed. If Britain could afford to build a strategic bomber force, it was certainly within the means of Germany, especially prior to the invasion of Russia, which is the time period we are discussing regarding the possibility of knocking out the U.K. Naturally, strategic bombing won’t destroy the UK’s manufacturing ability any more than it did Germany’s, but if it knocks just 10% off that 1940 figure, that’s 1500 less aircraft to overcome.
Regarding strategic bombing of Russian industry, well, yeah, Russia is immense. I am sure there would still be some targets for these fictional heavy bombers somewhere. Maybe at some point in this fictional war they get in a position similar to the summer/fall of 1942, and this time they would be able to actually seriously damage oil production in the Baku region(the source of 80% of the USSR’s oil production then).
Your point about Hitler not being under a strict treaty obligation to declare war is Correct. That doesn’t change the fact that he declared war on the U.S. (I believe I read somewhere a long time ago that he did it (quite uncharacteristically) out of a feeling of a kind of moral obligation to his ally, but I wouldn’t stake my life on it.) However, if the UK is out of the war in 1940/early 1941, the US and Germany would not be engaged in an undeclared naval war in the Atlantic when Pearl Harbor happens, and my hypothetical is that if Hitler does not go out of his way to declare war on the U.S., and the U.K is already out of the war, the U.S. probably does not decide to go to war to liberate a defeated Europe in response to the Japanese attack and instead just kicks the shit out of the Japanese because that is all public opinion wants in that case.
By the way, my acknowledging the correctness of what you are saying is not some mere ass-kissing-based deflection technique. You really have an impressive encyclopedic knowledge of this stuff; I have seen you in other threads on this topic.