Answer:
Nearly every "career" (called "lifers" during the war) soldier, marine, airman, or sailor that was Major or above (Lieutenant Commander in the USN), or a senior NCO...normally E-7 and above were WWII veterans. Some notable WWII vets during the Vietnam War were: Presidents Eisenhower, Kennedy, LBJ, Nixon, Ford; Generals Curtis LeMay, Maxwell Taylor, Harkins, Westmoreland, Abrams; Colonel Robin Olds (a WWII ace), just to name a few.