> The fact he knew phonetics just makes me believe he served or at the very least, was heavily exposed in another function.

This is just one data point, but I'm a random software engineer with no military or aviation background or interests, and I know NATO phonetics. I think it's not that uncommon.

(My main use case is spelling things over the phone.)

I learned the NATO alphabet for no better reason than it seemed useful over noisy communication channels, such as when on the phone in a data center with the HVAC going hard.

And so it has proved. That was maybe fifteen years ago; I'm so accustomed now, that I'll use it reflexively with everyone.

Anecdotally, I have observed that certain professions are inclined to treat those that use it with more respect.

Or just wanted to know phonetics for any other reason. They're not that hard and they're pretty useful on the phone.

I find these days they're pretty common with regular old customer service reps spelling out anything over the phone.

I was an Army combat medic and I know the NATO alphabet, despite never having been in an airplane cockpit.