She added, “@Delta sucks.”
Ms. Coulter went on to complain that Delta “spends all this $$$ on beautiful aircraft & then hire Nurse Ratchets as flight attendants & gate agents,” a reference to Nurse Ratched, the character known to be an overly strict enforcer of the rules in “One Flew Over the Cuckoo’s Nest.”
She even posted on Twitter a photo of the passenger she said had taken her seat.
In a statement, repeated on Twitter, the airline criticized Ms. Coulter for “posting derogatory and slanderous comments and photos in social media” about its employees and customers. Delta said it was “disappointed” in Ms. Coulter and called her actions “unnecessary and unacceptable.”
The airline said it would refund her $30 for the preferred seat she bought, adding, “Delta expects mutual civility throughout the entire travel experience.”
She ridiculed the $30 refund, saying on Twitter that it cost her $10,000 of her time to select the seat she wanted, investigate the type of plane and periodically review seat options.
In an email on Monday, she wrote: “I spent time ‘reserving’ — that term has a flexible meaning at Delta — a specific seat, and that’s my hourly rate. I looked up the aircraft, considered my options and booked the seat I wanted. I checked back to see how the flight was filling up to review my options again. I had reasons for choosing 15D, not 15A, or any other seat.”
The airline’s statement appeared only to incense Ms. Coulter, who continued the fight late into Sunday night and early Monday morning.
She wrote on Twitter: “I have been the picture of politeness. If I treated customers they way @Delta does, I’d deem ‘facts’ impolite, too.”
In her email, she complained that it was not enough for “Delta to boss customers around when we’re in their control.”
“Now they’re policing our behavior after we’re off the plane,” she wrote. “Perhaps they should spend less time sneering at their customers’ post-flight commentary and more time investigating why they invite customers to prebook their seats online, only for their gate agents to go into the computer, cancel a reserved seat, print new tickets, and give a prebooked seat to another customer, who apparently wanted the same seat — but not quite enough to bother booking it in advance.”
In its statement, the airline said that Ms. Coulter had originally booked seat 15F, which was by the window in an exit row, but that within 24 hours of the flight’s departure, she changed to seat 15D, which is by the aisle.
“At the time of boarding, Delta inadvertently moved Coulter to 15A, a window seat, when working to accommodate several passengers with seating requests,” the statement said. “When there was some confusion with seating assignments during boarding, a flight attendant stepped in and asked that all of the passengers move to the seats noted on their respective tickets. All customers complied and the flight departed without incident.”
Ms. Coulter complained that the airline did not communicate the seat change before boarding.
“I was in the boarding area 90 minutes before the flight took off, but I was never called to the counter and asked to switch seats,” she wrote in the email.
The airline said that what started out as a complaint had turned into a “public attack” on its employees and customers.
Delta said it had learned about her complaint only after she began tweeting after the flight landed. The company said its social media and customer service workers tried several times to contact her to apologize but did not hear from her until Sunday night.