I will say that Doolittle was a great, great man who basically turned the war in our favor on the Japanese front. He created and designed the bombing of Tokyo which demoralized the japanese and made them question the emperor for the first time. He was air force so he obviously had little skin in the game for the marines. So I can see why it made sense to some people to combine them with the army for some efficiencies.
Not saying I agree with it, just that some of the people supporting it had the best interests of the military in mind while others were probably commies that wanted to weaken us.
The Air Force never should have been allowed to form as a separate branch.
Marine and Naval Aviation shows why.