noun: a common deragatory term used to describe someone who was not tough enough to hack it in the navy or marine corps, and thus has joined the united states air force.
Guidance counselor talks with student:
Student: I wanna serve my country.
Counselor: You have a 2.8 GPA, 980 SAT, no sports or clubs.
Student: What's get me into, Navy!? Marines!?
Counselor: No, neither. You can be an air fag.