 Following his promotion to major general on January 19, 1967, he assumed duties the following month as commander, Marine Corps Air Bases, Western Area/Commanding General, Marine Corps Air Station El Toro, California and earned his third Legion of Merit.Major General Thrash was ordered to the Republic of Vietnam in July 1969, for a one-year tour of duty as commanding general, 1st Marine Aircraft Wing in the I Corps Tactical Zone, and earned the Distinguished Service Medal for his outstanding performance of duty during this tour.Upon his return to the United States in July 1970, he reported to the Marine Corps Base, Quantico, for duty as deputy for education/director, Education Center, Marine Corps Development and Education Command.