Ever hear of the USAAF?
Nutz
of course, you silly goof! I'll well aware of the WWII (and prior) US Army/USAAF command structure, supply, and their interwoven dependance.
However, please do not assume that just because the two branches were under the same command that each unit within each branch had standardized parts, fuel, guns, uniforms, comms systems, tires, mechanics, training, or even secret handshake. We're still talking about two very different entities.