BANGOR — During the past decade, nearly 1.5 million U.S. Armed Service members walked down a second-floor corridor at quiet Bangor International Airport, either on their way home or on their way to war.

No matter if it was a holiday or 3 a.m., Maine Troop Greeters were there to welcome and wish them well.

But with conflicts in the Middle East winding down, the airport has seen a marked decline in the number of military flights. The flights might stop altogether later this year.

“We don’t know how much longer we’re going to be useful there,” Chuck Knowlen, board chairman of the group of 250 local volunteers, said this week during a meeting with Bangor’s Airport Committee.

So, the Maine Troop Greeters are launching an effort to preserve their history and vast collection of memorabilia for when there are no military men and women left to greet at the airport.

The organization has started a fundraising campaign in hopes of raising about $300,000 to set up a museum in the hallway where troops were greeted with handshakes, hugs and applause.

The construction of the museum should cost about $200,000, according to Knowlen, with an additional $100,000 to build an endowment to maintain the museum for years to come.

The museum will feature display cases in the hallway, containing patches, photographs and about 5,340 challenge coins collected over the years. Challenge coins are issued to commemorate a particular unit, battle or military campaign, and troops often leave them with the greeters as a thanks. There also will be an interactive display with information about the challenge coins and other memorabilia. Prospect Design of Portland will design the space.

The museum also will serve as a “healing wall,” Knowlen said, a memorial to those who walked down that corridor, stepped on a plane and never came home.

The Maine Troop Greeters, airport officials and the Bangor Museum and History Center applied for an Institute of Museum and Library Services grant last year to build a permanent display for the collection but failed to get the grant, likely because there were no matching funds, Knowlen said.

The group is turning to members of the public.

Knowlen said the Maine Troop Greeters would be reaching out to large donors, but anyone, with donations of any size, is welcome to contribute to the effort.

“We need to tell this story,” Knowlen said.

Bangor International Airport Director Tony Caruso said airport officials would help the Maine Troop Greeters with marketing and spreading the message about the need for funds.

Knowlen also announced an event planned for 1-4 p.m. Saturday, Armed Forces Day, on the second floor of the domestic terminal. It will honor Korean War Veterans who never got the welcome home they deserved, he said. The veterans will walk down the hallway to be greeted decades after their return to U.S. soil by Maine Troop Greeters and members of the public.

To aid the Maine Troop Greeters, visit www.flybangor.com/troop-greeters. Select “How To Help” from the menu, and click the “Make a donation” option. People can contribute either to the museum effort or to the general operations of the organization.