The Secretary of Defense may provide transportation for the next-of-kin of persons who are unaccounted for from the Korean conflict, the Cold War, Vietnam War era, or the Persian Gulf War to and from an annual meeting in the United States. Such transportation shall be provided under such regulations as the Secretary of Defense may prescribe.
10 U.S. Code § 2647. Next-of-kin of persons unaccounted for from conflicts after World War II: transportation to annual meetings
Availability of Funds for Next-of-Kin of Vietnam Era Individuals
“Funds available in this Act [see Tables for classification] and hereafter may be used to provide transportation for the next-of-kin of individuals who have been prisoners of war or missing in action from the Vietnam era to an annual meeting in the United States, under such regulations as the Secretary of Defense may prescribe.”
Similar provisions were contained in the following prior appropriation acts: