An intoxicated female passenger on a British Airways flight to Boston was restrained after she tried to open an exit door mid-flight, say police.

The flight from London landed at Boston's Logan Airport at 1.30pm local time - about 30 minutes ahead of schedule.

In a statement, the airline called the passenger "unruly" and said the crew asked that police meet the flight upon arrival.

Massachusetts State Police took the 30-year-old woman into custody.

A police spokesperson told Sky News the woman was "unequivocally drunk", and the incident was not related to terrorism.

Authorities initially said a passenger had tried to force their way into the cockpit, but later said the woman attempted to open an exit door.

The suspect and other passengers were being interviewed by police and the woman "will most likely face charges", police said.

No other details have been released.