He had bought an extra seat on the flight so he could get his cello to Chicago for work. Typically, Kaboff just uses a seat belt extender to strap in his cello, but in this particular flight, the gate agent told Kaboff to go ahead and board the plane and that they would bring him one later.
After boarding the plane with his cello in the seat next to him, Kaboff encountered a "minor" setback, he said.
A flight attendant reportedly told him that he had to get off the flight because his cello was a "risk."
He said employees noted that it could not be strapped into the extra seat and it was touching the floor. Kaboff told the crew captain that he could simply use a seat belt extender to strap in his cello, they denied his request for one.
"I've flown American Airlines twice this month already, and I [didn't] have a problem," Kaboff told ABC News.
So Kaboff and his cello got off the plane.
His Facebook post about the incident received thousands of views.
In the end, Kaboff and his cello made the next flight to Chicago.
"The ground personnel and the gate agent said that someone's making an error with this and apologized on behalf of the airline," he told WJLA.
In a statement, American Airlines said, “We’re reviewing the issue internally and apologize to Mr. Kaboff for the inconvenience he experienced yesterday. Mr. Kaboff and his musical instrument were accommodated on the next flight to Chicago and our customer relations team has reached out to him directly."
American Airlines also said it plans to refund Kaboff the $150 he paid for his cello's seat. Kaboff said as of Thursday morning, he still has not received a refund.
Kaboff said the media attention he's received has been surprising and overwhelming.