Trump supporter Scott Koteskey had stowed his backpack in the overhead compartment and was about to settle into his window seat when he was verbally flogged by a fellow passenger.

It happened Saturday on board an Alaska Airlines flight from Baltimore to Seattle.

“She immediately asked me, ‘Did you come to cheer or to protest?’” Scott told me as he recounted the ordeal.

“As I was sliding into my seat I told her I came to celebrate democracy,” he said.

Scott had traveled all the way from Kalispell, Montana, so he could stand on the National Mall and watch Donald Trump take the oath of office.

“I’m a Trump supporter and I’m a patriot,” he said.

He said the woman, seated in the middle seat, went “from zero to 60.”

“There was no discussion or escalation. It was her coming out of the gate swinging at me with insults,” he said.

“She said, ‘Shame on you and all of the cockroaches that supported him,’” Scott recounted. “She called me fat and she said, ‘F— you.’”

About three minutes into the verbal assault, Scott pressed the record button on his cell phone. What he filmed has since gone viral.

“You pretend you have the moral high ground but you put that man’s finger on the nuclear button,” she said. “That man doesn’t believe in climate change. Do you believe in gravity? Did you know gravity is just a theory?”

Exasperated flight attendants tried to calm the hysterical woman, but she would not comply with their demands.

“Have some respect,” she told one of the flight attendants.

Scott said it was a bit ironic that she would demand respect while she was disparaging a fellow passenger.

At one point, the unidentified woman threatened to vomit in Scott’s lap.

“I’m going to throw up right in your lap. You make me sick. Don’t talk to me. Don’t look at me. Don’t you dare even put your arm on that rest. You disgust me,” she reportedly told the bewildered Trump supporter.

Police were eventually summoned to remove the foul-mouthed woman from the jetliner as other passengers cheered and chanted, “USA, USA.”

“She was definitely causing a big disturbance for everyone on the plane,” Scott said. “And I was relieved I wasn’t going to be harassed for a five-hour flight.”

It turns out this story has a happy ending. A standby passenger — hoping to return home to see his wife and daughter — was given the anti-Trump woman’s seat.

Scott said the man was a registered Democrat and he was taken aback by the woman’s hysterics.

“He was very, very civil and we had some great discussions,” Scott told me. “He said it doesn’t matter the disagreements we have — we’re all Americans. We should respect each other.”

And that’s the moral of this story, folks.

“No matter what we believe in, no matter what our political views, we have to treat each other with civility and respect no matter what,” Scott said.