The American Medical Association (AMA) has summarised the situation regarding taking a commercial flight in these Covid-19 times. Its appraisal is much in line with IATA’s review which BTN also covers. (See IATA and Covid-19 in this week's BTN)
The risk of contracting coronavirus disease during air travel is lower than from an office building, classroom, supermarket or commuter train.
According to AMA the virus that causes Covid-19 is emitted when someone talks, coughs, sneezes, or sings, mainly in droplets that can be propelled a short distance, and sometimes in smaller aerosol particles that can remain suspended and travel further. Another person can be infected if these particles reach their mouth or nose, directly or via hands. Transmission via surface contact is also important in some cases.
Air enters the cabin from overhead inlets and flows downwards toward floor-level outlets. Air enters and leaves the cabin at the same seat row or nearby rows. There is relatively little airflow forward and backward between rows, making it less likely to spread respiratory particles between rows.
The airflow in current jet airliners is much faster than normal indoor buildings. Half of it is fresh air from outside, the other half is recycled through HEPA filters of the same type used in operating rooms. Any remaining risk to be managed is from contact with other passengers who might be infectious. Seat backs provide a partial physical barrier, and most people remain relatively still, with little face-to-face contact.
Despite substantial numbers of travellers, the number of suspected and confirmed cases of in-flight Covid-19 transmission between passengers around the world appears small. In comparison, a study of Covid-19 transmission aboard high-speed trains in China among contacts of more than 2,300 known cases showed an overall rate of 0.3% among all passengers. Onboard risk can be further reduced with face coverings, as in other settings where physical distancing cannot be maintained.