Police officers physically removed a woman from a Southwest Airlines plane before it took off from Baltimore.
The incident is the latest passenger scuffle to be captured on video and magnified on social media.
After saying she was severely allergic to animals - there were two dogs on board - the woman refused the crew's request to leave the plane.
The crew then called on police to intervene.
A film producer recorded the ensuing struggle between the woman and officers and posted it online on the flight to Los Angeles.
The scene from Tuesday night was reminiscent of an April incident in which security officers yanked a man out of his seat and dragged him off a United Express flight in Chicago, sparking a public outcry about shoddy treatment of airline passengers.
Southwest, perhaps learning from United's initial hesitant reaction, immediately apologised.
VIDEO: Woman dragged off Southwest Airlines flight! pic.twitter.com/ih49KlqIds— KEEM 🍿 (@KEEMSTAR) September 27, 2017
"We are disheartened by the way this situation unfolded and the customer's removal by local law enforcement officers," Southwest spokesman Chris Mainz said.
Mr Mainz said the woman had reported she had a life-threatening pet allergy and the incident began quietly near the back of the plane, passengers said, as Southwest employees - including one of the pilots - talked to the woman.
Mr Mainz said the airline offered to re-book her on a flight the next day, but she declined - hers was the last flight of the night.
Airline employees ended up calling police, and the officers asked her to leave.
One officer pushed her from behind while another pulled her from in front, the video showed.
"What are you doing?" she asked. "I will walk off. Don't touch me!"
"All right, let's walk. Let's walk," one of the officers answered.
One passenger urged the woman to file a complaint, others urged the woman - who has not been identified - to walk off the plane so she would not get injured.
She could be heard identifying herself as a professor and told officers she needed to get to Los Angeles because her father was having surgery the next day.
"She put up a pretty ferocious fight to not be removed from the plane," said Bill Dumas, the film producer who took the video.
Mr Dumas said the police officers "were in a very, very tough situation" because of the woman's resistance, and Southwest did not have much choice because the plane would not take off until the woman left.
Southwest does not notify passengers ahead of time about animals on board.
"In most cases, we can separate the animal from customer with an allergy," said Mr Mainz, the Southwest spokesman. "The onus is on the customer to tell us what their needs are."
United was widely condemned after security officers in Chicago dragged a 69-year-old man off an overbooked United Express flight to make room for crew members flying to their next flight.
United CEO Oscar Munoz was excoriated for initially blaming the passenger, who lost teeth and suffered a concussion and the company reached a settlement with the passenger for undisclosed terms.