i liked the Vietnam era USAF uniform. You could moonlight as a Greyhound bus driver without having to change clothes.
Yeh I got mistaken for a postman once when I was an ROTC cadet in the '71 - '73 time frame. We wore the standard uniform but with unique metal (cadet officers) or cloth (cadet enlisted) rank insignia, as well as cap device. On a base, you'd get saluted because the cap device made it look like you were an officer, even though we wore the enlisted cap without the silver edging. (Today AFROTC cadets wear the officer style cap, or did the last time I saw one anyway.
We even wore the old 1505 khaki uniforms. The metal rank insignia did not work well with those, since there was no small collar version, and they were rather large and heavy devices. (Now they wear epaulet covers on their shirts, just officers, and have gone to a stripes scheme, similar to the ones of Navy officers).
Still, I don't think I'd like that Billy Mitchel collar much. Although the uniform looks better to my eye than the Hap Arnold "zoot suit" style. (the wide lapels interfere with display of the ribbons for example)