John Hagerman's first job with NACA (1943-1951) fulfilled a dream he had since he was 12 years old.

John then worked at Redstone Arsenal (1951-1955) on the Redstone and Jupiter Rockets and then with Werner Von Braun on his satellite program before it was taken over by the Navy.

At WPAFB (1955-1978) he tested the Avro supersonic bomber and the subsequent Avro car. Calculations on boundary layer control slots on the F-4 from the capture area to exit free stream, John's first brush with internal aerodynamics, was on a desk calculator not a computer. John and two colleagues at the Air Force Flight Dynamics Laboratory were involved in solving the transonic aerodynamic problems in the wind tunnel on several fighters such as the F-105, F-8, F-111, F-15, and C-141. The test techniques, when applied on the C-5A, resulted in unheard of agreement of flight-to-wind tunnel test data (including engine effects) under 2%. This was a first and not repeated since. John and his colleagues developed the transonic testing techniques using CAD-CAM before it was released to NASA. When accomplishments were presented to the chairmen of all the NASA committees, John suggested forming a Transonic Testing Technique (TTT) committee with representatives from several government laboratories to bring NASA up to speed. Advancements in the state-of-the-art of visual flow and its analysis was a big by-product of the TTT, particularly in the use of water tunnels. John eventually became the Air Force's aerodynamic troubleshooter.

GD Convair (1978-1986).

Over 25 years of active membership in AIAA.

John worked on almost all Air Force aircraft, atmospheric missile systems, some helicopters including X-1 through X-29 series during his career.