A British Airways flight from San Francisco to London was diverted to Vancouver after crew members fell ill.
Twenty-five members of the crew of the Airbus A380 including three pilots were taken to hospital for medical checks as a precaution but were later discharged.
The airline declined to comment on the cause of the problem was on Monday night or what their symptoms were.
There has been no confirmation over how many passengers were on board the A380 superjumbo but none had felt unwell.
BA said: “We are sorry for the delay to our customers’ flight but the safety and wellbeing of our customers and crew is always our top priority.
“The flight from San Francisco diverted to Vancouver after members of the cabin crew became unwell. Our ground team at Vancouver has arranged hotel accommodation for the customers and will book them on alternative flights as soon as possible.”
The airline has started an investigation into the incident.