Vientiane, Laos(CNN) For 45 years, Bill Gadoury has been looking for answers.
During the Vietnam War, Gadoury served for a year in Thailand and then moved to Laos to help brief commanders about pilots and crew members who never returned from their missions. In 1984, he joined the U.S. Embassy in Laos with the task of finding U.S. airmen who are missing in action.
On Monday, he was recognized by Secretary of State John Kerry, also a Vietnam War veteran, for dedicating his life to searching for the remains of U.S. servicemen who were never recovered.
Today he leads three teams, 58 people all, looking for remains -- a much smaller contingent than is looking for those MIA in Vietnam. It is painstaking work excavating wartime crash sites, often in dangerous terrain, before identifying and repatriating remains back to the U.S.
Gadoury last saw Kerry 24 years ago when he testified before the Senate Select Committee on POW/MIA Affairs, which Kerry used to co-chair along with Arizona Sen. John McCain, who was himself a prisoner of war during Vietnam. The panel was convened under President George H.W. Bush to investigate the fate of U.S. service personnel listed as missing in action.
"He was our link to possibilities and to realities," Kerry said of Gadoury when the two men met again Monday in a hotel in Laos.
Kerry and Gadoury reminisced about their time flying over Laos in 1992 looking for remains during Kerry's first fact finding trip to the Southeast Asian nation.
READ: Family's anguish in 45-year search for MIA pilot
"You remember flying around in that Russian helicopter, holding your breath every second in the air," Kerry recalled. He recollected that landing on a rice paddy was "beautiful and haunting. You could sort of feel a firefight around the corner."
Gadoury said that environment "gives you the sense of the terrain that we had to deal with back during the war, and what we were up against." And he noted, "It's the same terrain that we're still up against now as we're going back to try to locate and recover people."
A few seconds of quiet passed, with neither man saying a word, before they talked about the ongoing efforts and what work remained.
Having identified the remains of 271 airmen, Gadoury said his team has 302 still unaccounted for, with solid leads on about half of those cases. He has 75 cases identified for excavation.
With the easier sites in Laos examined, his teams have now moved into the mountains, where the terrain and weather make their job even more difficult.
Gadoury hopes that within the next 10 to 15 years he can complete the mission and account for all of those lost.
"Like World War II, I think in the end there's going to be those cases that we just aren't able to locate. There are no witnesses," Gadoury acknowledged. "But we'll do our best, like we've been trying so hard to do over the years."
Kerry called the effort the "largest, most comprehensive, most enduring examination of what happened to people in war in the history of warfare."
"I'm as proud of this as anything I've been engaged in," Kerry said. "No country has ever done what we did. I don't know of any other nation in the world that goes to the lengths we go in active duty, military people digging at active sites, pulling up the remains of a C-130, or helicopter, or something, in order to complete the mission."
Kerry's visit to Laos, only the second by a U.S. secretary of state since John Foster Dulles in 1955, is part of an effort by the Obama administration to normalize relations with the nation after decades of postwar estrangement and mistrust.
READ: Obama to push to clear leftover Vietnam-era bombs
In addition to programs in health education and energy, the U.S. has been steadily increasing its funding to help Laos eliminate an estimated 75 million unexploded cluster bombs remaining from the U.S. bombing campaign during the Vietnam war.
Ahead of his landmark visit to Laos this fall for the ASEAN summit, President Barack Obama is preparing to launch a major initiative to help Laos solve the unexploded ordnance problem once and for all, senior administration officials told CNN.
The budding relationship between the U.S. and Laos and the growing U.S. investment in the country seems to be paying off.
Gadoury said Monday that the Laotian government has become increasingly more cooperative on the MIA issue, asking U.S. officials to visit local sites like schools and clinics where remains are through to be located.
"The people in those areas understand that we're helping them and in return we hope that they will help us," Gadoury said.
At a separate session with embassy employees and their families, Kerry singled out the work of Gadoury and his team as "heroic."
"I would say that probably 99% of Americans don't know that they're here doing what they're doing, but for a lot of Americans, this is one of the most important missions in the world because they're still missing their loved ones and they don't have closure," Kerry said. "And people deserve and want closure. War has terrible, lingering scars, and where you have an ability to be able to address them, we should."