Aside from a single dog tag and pilot survival gear recovered in 1994, his family has been left wondering whether they would ever be able to lay their son to rest.
First-year Air Force Academy cadet Amy Young received a bracelet with Walling's name on it 22 years ago to wear in remembrance of her missing-in-action comrade, a symbol of the commitment members of the armed services have to never forget one of their own.
"I have had this MIA bracelet for 22 years. I got it as a freshman in the Air Force Academy, and it's just a way for us to help the families of our missing airmen know that regardless of anything, we remember and we are with them," Young said.
"I asked for one from a pilot and from someone who was from Arizona, where I'm from, and I got his."
Several weeks ago, Young said, she was scanning a list of military burials sent out from the Pentagon to Air Force installations and found Walling's name.
After verifying that it was the same person as the pilot listed on her MIA bracelet, she said she jumped at the chance to help memorialize Walling, who was born in Phoenix, in any way she could.
On Friday, Young, now a lieutenant colonel in the Air Force, a T-6 instructor pilot and chief of group scheduling at Sheppard Air Force Base's 80th Operations Group, will lead a four-plane missing man flyover at Arlington National Cemetery where Walling will finally be laid to rest with full military honors as a lieutenant colonel.
She'll also get to meet members of Walling's family and return the MIA bracelet to them, something she says feels like winning the lottery.
"I'm so fortunate; I'm so blessed to be in a position to say `thank you' to him and to his family," said Young, who is from Carefree, Ariz. "To be able to have his bracelet and to have him recovered and brought home to the family, it feels like one in a million; it feels like winning the lottery."
Young said bone fragments recovered from the crash site in Vietnam in 2010 were positively identified as Walling, and his family will get closure after years of living in uncertainty.
Walling's plane was shot down in an area with dense vegetation that prevented recovery efforts for several years.
Young said that in the years since she has started wearing Walling's bracelet, she's had the chance to get to know friends and fellow service members who served with him.
Even though he was shot down before she was born, Young said she feels like she knows him.
"I've received emails from folks he went to school with, friends, and people he served with. It's kind of an odd feeling to be so connected to someone who was shot down before I was born," Young said.
And when asked whether it will feel strange to not wear the bracelet after all these years, Young said she only wants one thing.
"It's going to be odd to be without it, but it's going to be uplifting to be able to give it to the family," Young said. "To be able to bring them some closure is all that matters."