Well i certainly think if you take two pilots of the same caliber and put one in a p 40 and one in a 190 the 190 stick will win hands down every time.
Oh... that depends on a lot of variables. Two good pilots: probably, as the 190 is the faster plane. But then we haven't defined the parameters of the combat and the combat environment.
With two very new players, the outcome is even less certain, as the 190 pilot may have a hard time to get a weapons solution, with two pilots not being able to utilize their respective plane's strengths, the result will be somewhat more random.
Plane are just tools. Pilots acre craftsmen. Skill can overcome limits of cheap, crappy tools, but only so much. On there other hand, some tools are excellent, but require a big deal of experience and knowledge to be used correctly, those tools are wasted in the hand of a beginner.
So in the end it's "Pilot+Plane", with a lot of environmental variables thrown in.