Coulter wanted an aisle seat in the exit row with extra legroom, and reserved such a seat.
Atlanta-based Delta moved her to a window seat in the same exit row.
Ever since that fateful Saturday night flight, Coulter has unleashed a string of tweets that stretched into Monday, along with an appearance on a conservative talk radio show focused on the incident.
She called Delta "the worst airline in America" and tweeted that it cost her $10,000 of her time to "pre-select the seat I wanted, investigate type of plane & go back periodically to review seat options" — only to be moved to a different seat.
Coulter also tweeted a photo of a woman who she said was given her seat along with other passengers, called the woman "dachschund-legged," and tweeted that Delta hires "Nurse Ratchets as flight attendants & gate agents."
Delta responded: "We are sorry that the customer did not receive the seat she reserved and paid for. More importantly, we are disappointed that the customer has chosen to publicly attack our employees and other customers by posting derogatory and slanderous comments and photos in social media. Her actions are unnecessary and unacceptable."
The airline said "there was some confusion with seating assignments during boarding," and a flight attendant asked passengers to move to the seats noted on their tickets. Delta said it would refund the $30 extra that Coulter paid for the preferred seat.
@AnnCoulter We're sorry you did not receive the preferred seat you paid for and will refund your $30. (cont.)— Delta (@Delta) July 16, 2017
@AnnCoulter Additionally, your insults about our other customers and employees are unacceptable and unnecessary.— Delta (@Delta) July 16, 2017
On host Joyce Kaufman’s talk show on the News Talk 850 WFTL radio station in West Palm Beach, Fla., Coulter said "airlines and particularly Delta have gotten so completely out of control, it’s as if they are not a customer-oriented business anymore."
"This is what the flying experience has come, just like arbitrary rules," Coulter said. "You just have to lie back and take it unless you want to be dragged off the plane."
Delta in its statement Sunday evening said "what started out as complaints eventually turned into a public attack on the airline’s employees and customers."
Coulter said her comments about the other passenger were "nothing defamatory about the customer, other than that she was not tall."
Others might not have gotten the attention Coulter did when criticizing an airline, Kaufman said.
"But there are hundreds of thousands of people that fly around this country every day that get mistreated by airlines," Kaufman said. "It’s happening, and if someone high-profile pushes back, they ought to just apologize."