LM Otero/AP
The incident, which was filmed by a fellow passenger, took place on flight 1525 from Baltimore-Washington to Los Angeles.
It started when the passenger, who has been identified as 46-year-old Anila Daulatzai, told the flight crew that she had a "life-threatening pet allergy," Southwest Airlines said in a statement to Business Insider.
Daulatzai brought this to their attention because there was an emotional-support dog and a pet on the flight.
The airline said that for Daulatzai to remain on the flight, she would need to show a medical certificate.
"Our policy states that a Customer (without a medical certificate) may be denied boarding if they report a life-threatening allergic reaction and cannot travel safely with an animal onboard," a Southwest spokesperson said.
"Our Flight Crew made repeated attempts to explain the situation to the Customer, however, she refused to deplane and law enforcement became involved," the airline said.
After Daulatzai was removed from the plane, she was taken into custody and charged with failure to obey a reasonable and lawful order, disorderly conduct, disturbing the peace, obstructing and hindering a police officer, and resisting arrest, according to a report from the Los Angeles Times.
Lt. Kevin Ayd of the Maryland
The Maryland Transportation Authority did not immediately respond to Business Insider's request for comment.
Southwest Airlines apologized for the incident on Wednesday.
"We are disheartened by the way this situation unfolded and the Customer's removal by local law enforcement officers," a Southwest spokesman said in a statement. "We publicly offer our apologies to this Customer for her experience and we will be contacting her directly to address her concerns."
"Southwest Airlines was built on Customer Service, and it is always our goal for all Customers to have a positive experience," the spokesman said.
You can watch a video of the incident below: