LA-bound flight turns back to London after cabin crew and passengers mysteriously fall ill

A plane from London headed to Los Angeles was forced to turn back on Thursday after several cabin crew members and passengers became mysteriously ill.

The American Airlines flight AA109 turned back over about 1,600 kilometres out from London's Heathrow Airport where everyone’s luggage was seized for "checks".

One member of the cabin crew fainted and up to three other passengers, including a man believed to be in his 60s and another in his 40s, complained of feeling unwell, Mail Online reports.

Passengers were reportedly kept in the dark about the situation as their luggage was confiscated and checked by airport and airline authorities.

The airline has not commented on what caused people to feel unwell. Twitter users said officials boarded the plane to test the air before passengers were able to disembark.

Passenger Alan Gray, 41, told Mail Online he saw a flight attendant collapse while other passengers looked "ill" and "iffy".

'One of the flight attendants was walking down the aisle when she collapsed. Then up to six other cabin crew members said they felt light-headed and as though they were going to faint," Mr Gray said before the captain announced he was turning the plane around.

"The lights then came on in the cabin and there was lots of commotion."

Mr Gray said there were police cars, ambulances and firefighters waiting to escorted them off the runway before they were held on the tarmac for 45 minutes.

"Eventually, when we did dock, there was only one person who came on and he was monitoring the air," he said.

A spokesman for American Airlines confirmed the plane had turned around after a medical emergency and the cabin crew made the decision fly 1,610km back to London.

"We apologise to our customers for the inconvenience to their travel plans," the spokesperson said. All luggage was returned to passengers.

Morning news break – January 28