Ten members of the American Airlines crew were taken to hospital after the jet made an unplanned landing at Boston’s Logan Airport on Sunday night.
The busy plane had set off earlier off from Philadelphia bound for London Heathrow.
Reports in the US say the concerned cockpit crew deployed their own oxygen masks during the “medical emergency.”
The pilot reportedly advised ground crews in Boston “declaring a medical emergency, we have sick passengers, sick flight attendants… We have three pilots up front, we’re all A-OK.”
American Airlines said after the incident: “Flight 728 from Philadelphia to London Heathrow diverted to Boston after a possible odour was reported in the cabin.
The aircraft, an Airbus A330-300 with 154 passengers and a crew of 12 landed safely at 11.48pm and taxied to the gate.
Ten of the 12 crew members asked to be transported to a local hospital for evaluation; all were later released. No customers experienced any issues.