Re: Imagine the TOS Starfleet
We know that the authority the Enterprise answers to is a "combined service"
I think Kirk was referring to Starfleet being a combination of the Air Force, Navy, Army, Marines and Coast Guard.
I always got the feeling when watching TOS that the Federation itself was much younger than the spin-offs said.
"...the most elementary and valuable statement in science, the beginning of wisdom, is I do not know." - Lt. Commander Data, "Where Silence Has Lease"