I don’t really know how to structure this question, but yeah, why is always Naval and never Aviation?
A notable exception is the Stargate franchise, where Earth’s spacecraft are largely run by the US Air Force.
I think most generally it’s because naval analogues are probably the closest when you’re talking about large space-based fighting vessels. The air force doesn’t operate aircraft carriers, battleships, or destroyers. The navy, however, does (or did in the case of battleships). Those large sea based vessels often class quite nicely into a lot of sci-fi media for large ships.
The small ships you see are often based off of a carrier equivalent. Even when they’re terrestrially based, it makes a lot of sense to streamline your military structure to have just one “space force”, rather than trying to break it up into two entities like the “space navy” and “space air force”, each with their own standards and logistical supply networks.
That’s always been my take. The Navy has the experience with big-ship operations, and operating smaller craft from those large ships, and it’s supply and logistics would likely evolve from ocean to space faring ships.
The Marines are historically an amphibious force, an extension of the Navy, specialized in ship-to-ship and ship-to-shore operations; ship-to-surface would be the evolution of that.
