Senior airman

Between its approval on 30 December 1975 (with implementation 1 June 1976) and 19 March 1991, senior airmen wore sleeve chevrons with blue center stars instead of silver to distinguish them from the non-commissioned officer rank of "sergeant", also a pay grade of E-4.

Senior airmen must attend the six-week Airman Leadership School, the first course of the Air Force's college of enlisted professional military education, before being promoted to staff sergeant.

Senior airmen were promoted to sergeant after 12 months' TIG and completion of the now-defunct Non-commissioned Officer Preparatory Course.

Air Force personnel who supported the change argued that proper leadership training eliminated the need for a separate rank within the pay grade; moreover, the rank created disparity between individuals earning the same pay and benefits and, often, performing the same duties, since often there were no additional junior airmen in a given duty section for a new buck sergeant to supervise.

As of 1998[update], the USAF and the US Space Force are the only United States military services that do not have a non-commissioned officer rank at the E-4 pay grade.