On Wednesday, they returned as 21 grown men and women, visiting their now-peaceful homeland to commemorate the first of the "Operation Babylift" flights that eventually brought 3,000 Vietnamese children to the United States.
"It's coming home," said Canh Oxelson of Los Angeles, who was just 10 months old when he first left Vietnam.
"Though most of us don't have a lot of memories of Vietnam, for some strange reason it feels very comfortable," he added.
A total of 57 children were on board the hastily converted World Airways cargo DC-8 that took off under cover of night on April 2, 1975. Ho Chi Minh City, then called Saigon, was about to fall to North Vietnamese communist forces, and the children, many of mixed Vietnamese-American parentage, were seen as especially vulnerable to the expected privations to follow.
Mostly babies, and all of them orphaned or given up by their parents, they grew up as part of American families across the country, often in places where there was little or no Vietnamese community.
Although many have previously returned to Vietnam, they said this week's visit was especially poignant for having reunited so many of the original passengers - along with several members of the original flight crew.
"It feels different this time because I'm coming with all the other adoptees, and we've covered common ground," said Oxelson, making his second visit to Vietnam.
The adoptees arrived at Ho Chi Minh City's Airport aboard a World Airways DC-11 painted with the airline's original 1970s red and white markings. Filing past Vietnamese women holding American and Vietnamese flags, they were greeted by local officials in a VIP room dominated by a marble bust of North Vietnam's revolutionary leader, Ho Chi Minh.