Eights days ago, a suicide bomber infiltrated an American air base in Afghanistan, killing four Americans and wounding dozens more.
The fathers of one of the slain soldiers said he was on his way to collect his son's remains when he was booed by other passengers.
"It just takes me a moment to collect my emotions," said Stewart Perry.
He's the father mourning the loss of a son at the service for Sgt. John Perry.
"Most importantly, I want people to know about the heroic thing that my son did."
Stewart Perry said his son stumbled upon the suicide bomber before the bomber could reach his target -- the soldiers' 5K Veteran's Day run.
"He would've killed possibly a hundred, two hundred people. Who knows?" Stewart said.
He said his son's death comes at a time military service is facing disrespect. He says his family was even booed on the flight to bring his son's body home.
"And to hear the reaction of the flight being delayed because of a gold star family, and the first class cabin booing that, was really upsetting, and it made us cry some more," Stewart recalled.
Perry says that's why the American flag is sacred for service members, not just a symbol for protests.
"It's not for protest. It's for the death of the people who are saving us, that's what it's for," he said.
Perry also called out recent presidential campaign rhetoric.
"One example would be Donald Trump speaking badly about a gold star family, who I now am, and it also bothers me that people don't want to talk about the terrorism that killed my kid," he said.
A soldier's death defending his country. Leaving a father defending his son.
"And my kid was over there to help put a stop to this garbage, and he died."
Perry said the passengers that booed may not have known that he was a Gold Star father. The captain only said that a special military family would be getting off the plane first to make a connecting flight.
It was still no consolation to Perry, who said Americans in general need to be more compassionate, especially to the military.