It's probably valid. Looks like a Colt SAA in a Lawrence Model 120 holster. Basically, a Threepersons type, although Elmer Keith claimed it was his design.

But jet fighter pilots sometimes wore sidearms on their belts. You can find pics of Col. Robin Olds and other Phantom drivers with issued belt holsters for their .38's. Some had an extra retention strap to keep the gun secure during ejection.

In WW II, Air Corps crews can be seen with both belt and shoulder holsters. Seems to have been an individual choice. I've seen pics of both types in the same bomber crews. And some enlisted men wore .45s. I think this was more common in the China-Burma- India theater, where they would possibly bail out over wild jungles and were also very afraid of Japanese troops killing captives.

Helo crews in Vietnam seemed to all routinely wear sidearms although holsters varied. One photo shows a USMC door gunner lugging two M-60 MG's to his helo. His holster was a shoulder type adapted to belt wear.

Chic Gaylord mentioned making a version of his Federal Speed Scabbard for an AF pilot. The gun was a Colt Official Police, and the holster had an added retention strap. But he didn't show a photo in that article.

I was in the USAF in the 1960's and come to think of it, when I saw Navy aircrew, they all wore shoulder holsters and their knives were on their vests. Maybe the Navy was more particular about that than was the USAF. Frankly, in my career field, I don't think a supervisor ever paid attention to the holster that I wore, but it had to be a belt model. But I was a cop, not aircrew.