Mask Advocates Cite Plane Transmission Study in Call for Mandate

The 44-year-old man was chatting with his wife and son on a flight from Singapore to China earlier this year when he let his guard down, allowing his face mask to slip below his nose.

That lapse appears to have been how he became infected with Covid-19.

The case, cited in a recently published study of an outbreak among passengers on a January flight, is one of the first to document a probable transmission on an airliner and is reviving calls for government rules requiring masks. It comes as safety concerns raise questions about whether passengers will return in sufficient ...