Looking over my notes the possibilities in the air war jump out at me. First off the Brits substantially out built the Germans in new aircraft 1940-42. Ellis in 'Brute Force has some direct comparisons for aircraft production of the major nations. & German production 1941-42 is actually unimpressive considering their head start. French projections for aircraft production are not in Ellis, or other sources I've run across. May have to resort to French language sources. However one of my notes shows the French goal was to have a operational air force strength of 10,000 aircraft in 1942. This is close to what the Brits had globally in 1942 so its not unbelieveable. The US had less at the start of 1942, but a substantial chunk of US production was going to Britain, Dutch East Indies, Finnland, Latin America, USSR, ect... The French had just completed a massive reorganization of its aircraft industry 1938-39 and retooled for new models. The also had substantial orders with the US industry. 1,800 aircraft were to be delivered in 1940, 3000 on order for 1941 with more in negotiation.
Looking at German stats for 1941-42 the biannual count of operating machines rose from 2800 combat aircraft April 1940 to nearly 6000 at the end of 1942. While production in 1942 was near six times that combat and operating losses kept the front line operating units from expanding much beyond the 6000 mark. Obviously a lot more data is needed to get a handle on this, but the historical performance 1941-42 in production and maintiance does not favor Germany.
In terms of aircrew of pilot training the numbers are worse. The Brits had in 1939 streamlined and refocused their pilot training on the skills actually needed for fighting the war. The German Air Force did not accomplish this until 1942. 1939-42 the Germans also had a problem with flight instructor shortages. The periodic use of the school staff for combat operations constrained & sometimes halted flight training. The work around was to hand off finishing training to the operating units. Each group was suposed to have a small training squadron. But, operational demands left that incomplete as well. As early as 1941 the rookies out of school were going into combat prematurely. In this the French may have had a advantage over the Brits as well as the Germans. Inter war they had built of a reserve of pilots with a larger than usual number of flight hours. While older & not always suitable for combat from age their flight experience was stronger. the represented a very large pool of potiential instructors. In contrast Germany had not been able to seriously expand its pilot pool until after 1936. The average German pilot had under three years experience in 1940. It leaned heavily of a smaller number of veterans with long hours. Again the numbers need to be examined in detail, but the Allies seem to have a advantage in this as well.
I expect there are some similar problems in other sectors. its a question worth picking over in detail.