Research published by the US-based Centers for Disease Control and Prevention (CDC) shows coronavirus can spread easily among passengers on long-haul flights.
The report looks at the case of a woman who flew in business class from London to Vietnam in March.
Although she passed a temperature check, she developed symptoms in the days following the flight and tested positive just five days later.
Contact tracers managed to link her to 15 of her fellow passengers who also later tested positive for the virus.
However, there is a caveat - at the time face coverings were not mandatory on flights, and so it is unlikely most of the passengers were wearing masks.