The unnamed businesswoman, 27, flew from London to Vietnam during the early days of the pandemic, on 1 March.
She had a sore throat and a cough before boarding the 10-hour service, and tested positive for Covid-19 a few days later.
According to a study from the US Centers for Disease Control and Prevention (CDC) published in the Emerging Infectious Diseases journal, during the flight the woman unwittingly infected 14 other passengers and one member of cabin crew.
Of the passengers who transmitted the virus, 12 were sitting in business class, along with patient zero, where seats are spread further apart.
Two were seated in economy.
“The most likely route of transmission during the flight is aerosol or droplet transmission from case one, particularly for persons seated in business class,” said the study.
“The risk for on-board transmission of SARS-CoV-2 during long flights is real and has the potential to cause Covid-19 clusters of substantial size, even in business class-like settings with spacious seating arrangements well beyond the established distance used to define close contact on airplanes.”
However, it’s worth noting that the outbreak took place before the use of masks onboard flights was widespread.
The news comes as the CDC revealed that nearly 11,000 passengers have potentially been exposed to coronavirus on flights in the US.
The American public health body identified that thousands of travellers may have been at risk after investigating 1,600 cases of people who flew while infected with Covid-19.
However, the CDC said it is unable to identify how many people contracted the virus while on flights due to a lack of data.
“CDC is not able to definitively determine that potential cases were associated (or not) with exposure in the air cabin or through air travel given the numerous opportunities for potential exposure associated with the entire travel journey and widespread global distribution of the virus,” said a spokeswoman for the CDC's Division of Global Migration and Quarantine, reports the Washington Post.
“An absence of cases identified or reported is not evidence that there were no cases.”