As GPS receivers become smaller, a significant size contributor is their precision frequency references. This paper describes the development of a 1 in3, VHF, ovenized frequency reference suitable for use in airborne environments. A review of operational requirements for GPS frequency references identifies frequency stability, fast warmup, and low power as key requirements. This paper shows how these criteria are met with this frequency reference design. The producibility of this reference is addressed, focusing on manufacturing and testing techniques. Important to the design is parameter sorting of the crystals. A fast and efficient method for crystal sorting is described. Performance results for several production units are presented.