Another thought.
The symbol for Earthforces navy were a pair of wings. So this service might see it's heritage equally in the wet navies as in the airforces (as the first US astronauts were a mix of naval air wing pilots and airforce pilots), so their rank structure might reflect this in being an amalgam of airforce and navy rank structure.
Not so. The flightwings were only to indicate that the person wearing them is a qualified pilot. You see numerous officers and non-coms in blues that don't have the wings and as has been mentioned, Garibaldi, a security chief also had the wings. By-the-by it's not just a matter of qualification, as I recall if they don't log a certain amont of flight hours per month, then they loose their flight status and by extension, flight pay.
Same with Zack Allen; although, it seemed that he was brought on as a civilian security officer. But from "Sleeping in Light," it seems that Zack was part of Earthforce either before he came to Babylon 5 or after he left. IIRC, in that episode his EF security uniform also had wings on the sleeve. Not to mention that he "flew" a Starfury in the telemovie Thirdspace.
Reverand,
How do you figure the pilot episode ranks into your structure/illustaration? IIRC, there were different devices used on the epalutes.
I've always thought of "The Gathering" uniforms as a variant of the uniforms we saw in the series proper and in the telemovie In The Beginning. Almost a Class-B working uni, especially considering that the station recently went operational.