Dreyfoos graduated from the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts, in 1954 with a BS focusing on electronics, optics, and physics, assisted by MIT financing after the death of his father. Having also completed ROTC, Dreyfoos then served in the U.S. Air Force in Sembach, Germany, 1954–1956, commanding a 40-man photo lab critical to reconnaissance missions at age 22. Returning home, under the GI Bill he earned an MBA at Harvard Business School in 1958. Dreyfoos earned his pilot's license in 1960, and multiple ratings over time including airline transport pilot (ATP). He has owned six airplanes, including two Citation jets, and two turbine helicopters, all of which he flew single-pilot.