As far as I know, the fixed-wing flyboys were all commissioned, in all services. the chopper pilots in the Army were Warrant Officers. They got used up really quickly. But all pilots were volunteers. It takes to long to train them to assign draftees.

One of the major problems in Viet Nam was getting that combat ticket punched for the career officers. Then they got out. By the end of that 13 month tour, just when they were starting to get good at their job, they'd get pulled out and some boot put in their place.
The result was that the line officers, were all inexpereinced, or short. In fact, I guess you could say that for most of the enlisted men, too.

In the Navy it was a little better, many had multiple tours, but my impression of the military is that it was mostly a goof ball outfit, the officers cared more about their careers than their duty. I told my skipper as much during my man-to-man "shipping over" speech when I was leaving the Dewey. He said nothing to contradict me. I was offered a nice cash bonus to re-enlist and a chance to sew on my E5 stripe (even though I had already earned it by passing the exams). It was all screwed up, they were releasing me prematurely from my 2-year committment, but wanted to pay me to ship over.!) As it turned out, they let me sew on the stripe when I went to my home reserve unit anyway. E5 in thirteen months. It was some kind of record in my rate.

I could not believe how well the military had their shit together by the time we went to war in the Middle East. I sincerely believe the career officers and NCOs who survived the VietNam era committed themselves to reforming the military, and by the time of Desert Storm they were really, really good. I was impressed.