Duke is a retired aerospace engineer with thirty-five years working in industry and the DoD/civil service. The bulk of his career was spent at WPAFB working in engineering and program management in the acquisition career field. Unclassified weapon systems worked over the years included A-7, A-10, B-1, B-2, C-130, C-17, C-27, CV-22, VC-25, KC-135, E-3, F-111, F-15, F-16, F-22, F-35, F-117, H-60, T-1, T-3, T-6, T-38, T-46, and X-32.

Duke is also an amateur aviation/military historian with articles published in various magazines including FlyPast, Aviation History, Logbook, Military, USAFM Friends Journal and Aviation Art.