You might have seen the name Chase Irwin. He's a Nashville restaurant manager who became a little bit Internet famous and was hailed as a hero recently, after he aggressively called out a fellow passenger on United Airlines for "body shaming" a third passenger in a text message.

The whole episode never would have happened, Irwin told me, but for a ridiculously big change fee on another airline.

He had been in Oklahoma City for a graduation, and his ride to the airport got him there 12 hours before his scheduled departure. Switching to an earlier flight on Delta would have cost him $900, he said. So he scrapped that and bought a ticket on United Airlines instead.

That's what landed him in seat 15C of a United flight to Chicago, for the first leg of his trip, which had a 30-minute delay. As they sat on the tarmac, he said he had a clear view of the cell phone the male passenger diagonally ahead of him, in 14B, was texting on. 

"The guy had his phone out far from his face. The font size was really big. And I saw the words, 'sitting next to a smelly fatty,'" Irwin said. 

Then, Irwin said, he saw that the woman in 14A was crying, and looked like she was trying hard to push against the window away from the man. Irwin leaned forward and read the rest of the man's message. 

He grew incensed. Over the next few minutes he talked with two flight attendants, and worked out a plan with them to convince the man to change seats with Irwin, so that the woman wouldn't have to sit next to him.

Irwin, 34, who is about six feet tall and 200 pounds, told me he stood up and grabbed the shoulder of the passenger who'd been texting, who was about 5-foot-6 and "160 or 170," and seemed to be in his 50s or 60s.

"You're a heartless person," Irwin remembered saying, and ordered him to switch seats. "I wasn't quiet. I wanted people around him to see he was a jackass."

The other passenger actually said "thank you," perhaps not understanding the context, and Irwin said he sat next to the woman and tried to take her mind off the offensive message (which she had in fact read) for the rest of the flight. 

Based on Irwin's account alone, it might be hard to know what to make of this whole thing. The unidentified texter was impolite, but he did seem to be sending a private message. 

Meantime, Irwin used his size to act aggressively against another passenger on an airliner, with the apparent assent of the flight crew. 

However, the story only came to light because the woman passenger, Savannah Phillips, posted about it publicly afterward on Facebook--as a way to try to find Irwin and thank him for what he'd done. That post went viral (more than 1,500 shares so far), and commenters almost unanimously praised Irwin for his actions.

"The flight attendant kept trying to give him free drinks and told him that he was her hero," Phillips wrote. "He wasn't her hero--he was mine... I told him that he was a blessing sent to me and how thankful I was that he was there."

By the time his connecting flight landed in Nashville, Irwin, who is general manager of a bar there called Dierks Whiskey Row, said his company's corporate office in Arizona had seen her post and had contacted him. He and Phillips reconnected within hours.  

United Airlines told Newsweek, which reported on the whole incident: "We appreciate the efforts of the customer and would like to hear from Ms. Phillips to understand what occurred."