Miscast rank?

I should add that my great uncle did serve in WW II but through persistence after being turned did, the Army relented, and was put in an Artillery unit.

It does seem illogical that Fredric March is an enlisted man while Dana Andrews is an officer. It may not make sense in real life, but I think it works from a dramatic standpoint. It heightens the contrast between the two men's social status in their military and civilian lives. The enlisted man becomes an affluent bank executive while the officer becomes a lowly soda jerk.

Al Stephenson - There were only so many positions in finance and quite a few bank officials. Plus, Al was too old to be an officer. I thought he was in combat? If so, that would make even more sense that he'd be a Sargent.

BTW, Dashell Hammett was accepted in the Army in WW2 at the age of 48.

Fred Derry - Yes, priority was given to those who had college background but plenty of guys without a college background became pilots or washed out of pilot training and became bombardiers. Plus, some guys, maybe Fred, volunteered for bombardier training and never wanted to be pilots. Those guys had a leg up on the wash outs from pilot training.

Plus, the movie is somewhat unrealistic in that Dana Andrews and Fred March are too old for their roles. There were plenty of 18-20 Year olds without any college who became pilots/navigators/bombardiers.

Future senator Paul Douglas enlisted as a private in the Marine Corps in 1942 at the age of 50.

Not really.

In Fred's case the attrition rate for flight crews (both in combat and training accidents) meant that they were looking for men who could do the jobs needed - not necessarily those that fit a classing system. There were so many officers in this situation after the war that the Army offered a "Bootstrap" program where they paid you (and for you) to go back to college and get a degree so you could continue on with your career.

As late as the early 1980's the Army had a "High School to Flight School" program to replace the dwindling pilots choosing to leave the service after Vietnam. You had two years (up to four years under special circumstances) to get your AA and up 6 to get your BS after completing flight school - so up to four years being a Warrant Officer with only a High School diploma or GED was possible back then. Upon completion you could opt to remain a Warrant Officer and advance, apply to Officer Candidate School and become a commissioned officer if you wanted command billets, or leave the service taking your piloting skills for an Embry-Riddle (if needed because of not completing a degree in time or to add fixed wing) short course stint and become civilian pilot. Another outcome was going into something aviation related (or something entirely different if there was a need) as an enlisted member. Borderline bad eyesight and a flight surgeon that couldn't be convinced to change his mind kept me from starting flight school even though I had passed the AFEES physical; but luckily as it turned out I landed in Cavalry instead.

In Al's case, he was most likely drafted/joined in '44 after having deferments for family, or possibly even had a key 'supporting the war effort' position being in the bank that kept him from being drafted at all - and decided to join anyway. He could have possibly been an officer, maybe not, or chose instead to be enlisted. No one was forced to be an officer against their will. I remember in basic training three guys were singled out for OCS. All three turned it down.

Introduce a little anarchy. Upset the established order

Makes perfect sense. Although it helped, you did not need to have college to become an officer, Chuck Yeager being a prime example (although he went from enlisted to flight officer before being commissioned.)

And Al, an infantry sergeant, may have been in the National Guard before the war so he went in at the rank and specialty he had there. (For some reason, maybe something on his uniform, I got the impression he was a WW1 vet.)

The Guard is strange that way. I knew a lot of guys whose civilian lives were completely different from their military ones. I remember officers asking sergeants if it was possible to pick up any overtime because they worked for them. (Conflict of interest, i'd imagine.) And i knew guys who were enlisted infantry, but who had degrees and occupations that could have let them be officers in other branches. They told me they specifically wanted to do something different than their day jobs.

"I'll do the masterminding around here." -Sgt. Stryker, "Sands of Iwo Jima"

Not only miscast but way out of whack. Look at the service hashtag on Al's sleeve. SIX of them. Each on indicates three years of service. That would have meant that Al was in the army for over 18 years. That makes no sense in the storyline. Al worked at the bank before the war and made enough bucks to live in that nice apartment. The movie implied he was a draftee/enlistee and fought in the Pacific theater. Having those service hash marks on his uniform is a HUGE mistake to the character.