The rank titles, at this time, from bottom to top, were: Private (no stripe), Private First Class (one stripe), Corporal (two stripes), Sergeant (three stripes), Staff Sergeant (four stripes), Technical Sergeant (five stripes), Master Sergeant (six stripes and tithe only rank approved for First Sergeant Duties).
20 FEBRUARY 1950 - General Vandenberg directed that from this day forth, enlisted personnel of the Air Force will be called "Airmen" to distinguish them from "Soldiers" and "Sailors." Formerly, Air Force enlisted personnel were still called "Soldiers.
24 April 1952 - Studies made in 1950 and 1951 proposed to change the enlisted grade structure and was adopted by the Air Council and Chief of Staff in March 1952. The change was embodied in Air Force Regulation 39-36 on 24 April 1952. The primary objective desired in changing the airman grade structure was the restriction of non-commissioned officer status to a group of higher grade airmen sufficiently small in number to permit them to function as non-commissioned officers. Plans for improving the quality of non-commissioned officer leadership hinged upon this change : now that the change was made, plans for investigating and improving the quality of this leadership began.
The titles of the ranks changed (although not the chevrons). The new titles, from bottom to top, were: Basic Airman (no stripe), Airman Third Class (one stripe), Airman Second Class (two stripes), Airman First Class (three stripes), Staff Sergeant (four stripes), Technical Sergent (five Stripes) and Master Sergeant (six stripes).
At that time, it was planned to develop new insignia for the three classes of Airmen (First, Second, and Third). Preliminary sketches of proposed insignia have the stripes at a horizontal level, reserving the angled stripes for the toop three ranks to differentiate Non-Commissioned Officers (NCOs).
DECEMBER - 1952 - The proposed-new-chevrons for the three lower ---- airman grades are approved by General Vandenberg. However, the procurement action is deferred until existing stocks of the current chevrons are depleted. This is not expected to occur until June 1955.
22 SEPTEMBER 1954 - On this day the new Chief of Staff, General Nathan F. Twining, approves a new distinctive insignia for First Sergeants. It consists of a traditional diamond sewn in the "V" above the grade chevron. Recommendations for adoption of this distinctive insignia were advanced by two commands : Strategic Air Command (SAC) and Air Training Command (ATC). The suggestion from ATC was included in an appendix buried in a February 1954 ATC Personnel Planning Project, while the SAC NCO Academy, March AFB, CA, proposed the design on 30 April 1954 to the Air Council.
21 SEPTEMBER 1955 - The availability of the distinctive First Sergeant insignia is announced.
12 March 1956 - In 1952 General Vandenberg approved a new chevron for Airman, First, Second and Third Classes. The purpose of this change was to increase the prestige of the Staff, Technical and Master Sergeant chevrons. The stripes were to change from the angled design to horizontal. However, due to the supply of chevrons on hand, action was delayed until supply had been deleted, which happened in early 1956. The decision to change the design was resubmitted to General Twining on 12 March 1956. The Chief replied in a short informal memo stating "No change to be made in insignia."
JANUARY - JUNE 1958 - The Military Pay Act of 1958 (Public Law 85- 422), authorized the additional grade of E-8 and E-9. No promotions to the new grades were made during Fiscal Year 1958 (July 1957 through June 1958). However, 2,000 individuals were expected to be promoted to the grade of E-8 during Fiscal Year 1959. On the other hand, in accordance with Department of Defense instructions, no promotions to grade E-9 were to be made in Fiscal Year 1959. During May and June 1958, almost 45,000 Master Sergeants from all commands were tested with the Supervisory Examination as a first step in the final selection of 2,000 for eventual promotion to E-8. This test screened out approximately 15,000 applicants, permitting approximately 30,000 to be further screened- by command boards from which 2,000 would be selected initially.
JULY-DECEMBER 1958 - The two new grades (E-8 and E-9) were particularly welcome in that they would relieve the "compression" in the grade of Master Sergeant. However, because the numbers had to come out of the former Master Sergeant authorization, no improvement in promotion opportunity resulted to the overall enlisted structure.
Information courtesy of U.S. Air Force News Service, and the Air Force Historical Research Agency