Do you have a source for that? Last time I checked, Uncle Sam was issuing .38's to pilots until the middle of the 1980's.
I think he's referring to the Phillipine-American War, when the local Moro tribesman were fighting through injuries sustained from the then-standard .38 Long Colt pistols, with the help of some "performance-enhancing" drugs. The U.S. forces temporarily switched to .45 Colt revolvers, and found the heavier bullets to be more effective. This prompted the search for a new service pistol, and the criteria of "not less than .45 caliber" was put forth, along with a preference for a semi-automatic design, if possible.
As for the fact that American aviators were issued .38 revolvers until fairly recently, that doesn't say much for their suitability as a combat weapon. I'm a flight officer in the Navy, and the pistol I'm given when I go flying is strictly a last-ditch survival tool - effectiveness and stopping power aren't primary considerations. If I have to bail out, my new mission becomes getting myself back to friendly forces, hopefully without encountering any enemies at all. I don't transform into a ground soldier and start looking for bad guys to kill.