BANGOR — Bill Knight was at Bangor International Airport at 2 a.m. one day in 2004 when filmmakers Aron Gaudet and Gita Pullapilly first met him. He was standing in the hallway, shaking hands with troops.

Just hours earlier, doctors told Knight he had prostate cancer, Gaudet and Pullapilly said. That didn’t matter much. He wasn’t going to miss the chance to greet and shake hands with troops while shouting, “Welcome home, heroes!”

Knight, 91, died on Christmas Day at the Maine Veterans Home in Bangor. Gaudet and Pullapilly were at his bedside for part of the day. The couple created a documentary, 2009’s “The Way We Get By,” that highlighted the story of Bangor’s Troop Greeters. The film received international accolades, and Knight was one of its focal points.

Gaudet and Pullapilly said Thursday that they told Knight, as he was laying unconscious, “We love you, we’ll miss you, but it’s time to let go.”

Knight had undergone hip surgery and suffered from dementia and other serious health issues recently. His ailments had kept him away from the airport for the past couple of years.

Jerry Mundy, another one of the greeters featured in the film, spent Christmas Eve at the Maine Veterans Home, comforting his longtime friend, Gaudet and Pullapilly said.

Nine years ago, Pullapilly came with Gaudet to Bangor to visit Gaudet’s mother, Joan, for Christmas. The couple accompanied Joan to the airport, where she went to greet troops. That’s where they first met Knight. They followed him home to talk and learn more about his life, and were inspired to shoot the documentary, according to Pullapilly.

Knight, a 32-year military veteran, struggled with poverty and near homelessness. His story tugged at the hearts of countless people around the country and globe who saw the film, Gaudet said. Knight, who outlived two wives and two daughters and saw his fair share of hardships, still saw troop greeting as his most important duty up until his health became too poor to continue in recent years.

“We basically started making ‘The Way We Get By’ because of him,” Pullapilly said.

After the film debuted at the Camden Film Festival, Knight traveled the country with the filmmakers, receiving admiration and praise from across the nation, according to Gaudet. It showed Knight that “his story was serving a purpose,” Pullapilly said.

Veterans took to social media websites on Christmas Day and the day after to share memories of their encounters with Knight from when they passed through Bangor International Airport, or just to thank him for his years of dedication.

One veteran wrote, “god bless that man shook his hand several times it was always a warm feeling to shake his hand Great patriot will be missed.”

Another soldier called Knight a “legend.”

Others sent their memories and condolences to “The Way We Get By” Facebook page.

When veterans returned from war, Knight was often the first person troops asked about, according to Gaudet.

“He’s touched so many lives,” Pullapilly said.

Chuck Knowlen, chairman of the Bangor Troop Greeters, said Thursday that the organization wouldn’t be what it is today without Knight’s influence.

“He was dedicated to the troops,” Knowlen said Thursday. “His life was the troops.”

“His heart was right here at the airport,” Knowlen added.

Gov. Paul LePage and first lady Ann LePage issued a statement Thursday reflecting on Knight’s death.

“We have lost a man who reminded us time and again about the American spirit and how fortunate we are to live in a free nation,” Gov. LePage wrote. “Maine was fortunate to have known Bill, and we honor his memory by continuing to support our service members every day for their courage and sacrifice in defending our freedom.”

Brookings-Smith Funeral Home is handling arrangements, but no final plans are expected until Friday. The Troop Greeters, Gaudet and Pullapilly said they are waiting to hear what those arrangements will be before determining what remembrances or recognitions they might contribute.

Gita and Pullapilly said they’ll have a lasting image of Knight — the first man standing in the hallway to the airport terminal, shaking hands with troops coming home or, on more somber occasions, heading to war.

Pullapilly said a friend sent her a text message after hearing news of Knight’s death.

“I can’t help thinking someone on the other side was there saying, ‘Welcome home, hero,’” when Knight arrived, the text read.