Lt. Col. Wittenborn enlisted in the Air Force Reserve, 442nd MAW, Richards-Gebaur AFB, Mo., in February 1967. Returning from basic training, he entered the OJT 70210 personnel specialist program. In June 1971 he returned to Lackland AFB, Texas, to enter OTS. After graduation he went to Laredo AFB, Texas, to UPT and graduated in August 1972. He returned to Richards-Gebaur and the 442TAW flying the C-130A, E and B models.
In he moved with members of his unit to Peterson AFB, Colo., to start a new C-130 tactical airlift wing, the 303rd TAW, with two squadrons and a total of 16 aircraft. Wittenborn was the chief of the wing aircrew standardization and evaluation unit in charge of maintaining tactically qualified aircrews to fly the unit-equipped aircraft. During his time at both Richards-Gegaur and Peterson, he participated in numerous TDY assignments throughout the world. He was assigned TDY to Nellis AFB, Nev., for several Red Flag exercises. From 1982 until he retired in 1993 he spent several weeks each year at the Test Pilot School at Edwards AFB, Calif. He flew out of Howard AFB, Panama, several weeks out of each year from 1972 until he retired in 1993 in support of Operation Volant Oak and America's counter-drug program. From December 1990 until June 1991 he was assigned to RAF Mildenhal and Incirlik AFB, Turkey, in support of Operation Desert Shield and Desert Storm flying low-level tactical missions in northern Iraq. Wittenborn retired from the the Air Force Reserve in July 1993 after nearly 27 years of service.