Airman Basic (AB) is the lowest enlisted rank in the UNSC Air Force, immediately below Airman. The pay grade for Airman Basic is E-1.
Airman Basic is the only Air Force rank that has no insignia affiliated. The lack of uniform insignia for Airmen Basic is the impetus for the nickname "slick-sleeve," in contrast to all other enlisted Air Force ranks which wear their stripes/chevrons on their uniform sleeves.
The term of address for an Airman Basic is "Airman Basic," "Airman," or "AB."