You're mixing up terms here. Gravy seals is an insult term, used for typically out of shape people who are heavy into gun/militia/i-am-very-badass type culture.
The latter two are just ribbing jokes about the Air Force, from the other branches usually. My old (Army) boss used to tell me to 'take off your air force gloves' if he ever saw me with my hands in my pockets.
Absolutely. Just pointing out that one is strictly a pejorative, while the others would likely be viewed as 'someone in the airforce.' I think OP was wanting things more of the former, like gravy seals, meal team six, y'all queda, etc.
Or some new ones I've heard kicked around:
- Gravy Seals - 101st Chairborn - Chair Force pilots
...And so on...