What catch-phrase used by veterans instantly identifies in which branch of service they serve(d)?

All the way!

Marines: *Noises. Just...noises.*
Army: "Stupid rules? I love those!"
Navy: "Richard is just the best."
Air Force: "Sorry, $100,000 is just too low a salary, but thank you for the consideration."

“Good to go”

Whatever it is, it needs to be something that grew up like Hooah for dogfaces like me and Hoorah for the Jarheads. I recall reading a few years ago that some senior type wanted to have the Air Force start using Air Power as their catch phrase...

Devil dog, semper Fi, Jar head

Army or Marine: "You're Late!"
Navy: "Chief"
Airforce: "Wat Up???"
Coast Guard: "What time is it?"

MSgt Ken "Airsoldier" Collins-Hardy
- if it sounds like a growl, snare, bark, or grunt = Marines
- if reminds you every five seconds that they were a Navy aviator = Navy aviator
- sighing after waiting for three minutes = Army
- anything that sounds like luxury = Air Force

Asshole to Belly Button, Maggots!

Asshole to Belly Button, Maggots!

Proud to be a Grunt and a Rotor Head...