American Airlines Flight AAL38 with 129 passengers on board returned to Miami where it was met by police, it said.
They escorted a woman in her 40s off the plane, reports say.
She has been placed on a list of people barred from flying with American Airlines, pending further investigation, the airline said.
The Wednesday flight turned around less than an hour into its journey, according to tracking service FlightAware.
“American Airlines flight 38 with service from Miami (MIA) to London returned to MIA due to a disruptive customer refusing to comply with the federal mask requirement,” the airline said.
Passengers on the flight to London Heathrow were re-booked on to another flight for Thursday.
“Everyone was shocked,” one passenger told CBS station WFOR-TV after getting off the Wednesday flight.
Another passenger said she was disappointed.
“They wouldn’t really say anything, and I don’t believe they told the flight attendants anything either because they said all they could say was there was an extreme incident with a passenger and they had to turn around,” she told the station.
Airlines reported nearly 6,000 incidents involving unruly passengers last year and 151 in the first two weeks of this year, according to the Federal Aviation Administration. Most of them involved passengers who refused to wear masks.