Are you referring to the drag coefficient of the wing?
Yeah, basically the whole big diatribe about how the wing isn't, and can't possibly be because no one can do it, a laminar flow wing. The real genius of the wing is that the camber of the upper surface was moved rearward and the leading edge was brought to a sharper point. A lot like VLD and ULD bullets. And, the numbers he uses are for the P-51A at sea level vs. the P-51D. The -B/C were faster on less horsepower, true. But, they only had four wing mounted .50's not six. And, the -D could carry more weight.
Another thing, he constantly references the P47M. He uses it as one of his comparisons to the Ta-152-H. One, it never fought over continental Europe. And two, (he only references it once) there were only 130 built. His end conclusion is only partially correct that it was the P-47 that gave us air supremacy, not the P-51. Yes, the P-47 was probably THE major contributor, but due to it's limitations, and the pilots flying it (read: training biggest limitation) it wasn't as effective in the air as the P-51.
He goes off on other things too, like fighters being used in the ground attack role. They were actually stupendous in this role. specifically the P-47. The 20mm cannon, may be better individually than the .50 cal. But, due to construction and speed of the aircraft of that time, the .50 cal was more than adequate. 1900 rounds of .50 that will do the job is better than 236 rounds of 20mm, that will do the job but gives no aiming advantage. Not much of a comparison considering you have to cross back hours of hostile air space to get home. And, the list goes on. He uses a lot of charts to try and make comparisons. Charts that he says were pulled from manuals. Training in the USA and surviving over fortress Europe are two very different things.
My biggest pet peeve? "The greatest combat aircraft off WWII" The PBY Catalina. Yes, it was a well used and versatile aircraft. But, it wasn't exactly a "combat" aircraft. It didn't survive combat very well at all. And the single biggest issue to me? He never mentions Van Voorhis. Maybe he ought to look that up and put it on a chart somwhere's...
Hint:
https://www.honorstates.org/index.php?id=323355