With many governments loosening travel restrictions to restart economies, airlines have begun restoring flights that were put on hold as the coronavirus pandemic spread. Business is slow, as would-be passengers worry about being stuck in a cabin for an extended time with possibly infectious strangers. The record shows the risks aren’t negligible.
1. Has coronavirus spread on airplanes?
Yes. While there is still relatively little published research on the spread of the virus on airlines, an investigation into a March 2 flight from the U.K. to Vietnam suggested that one passenger transmitted the virus to as many as 14 others and a crew member. Twelve of these passengers were sitting close to the suspected first case, which matches the expected spread of this and other coronaviruses. The International Air Transport Association, the trade group for the world’s airlines, said that aside from this case, an informal survey of 18 major airlines identified four episodes in the first three months of the year of suspected in-flight transmission from passengers to crew, and a further four where one pilot appeared to give the virus to another. This group of airlines represented 14% of global air traffic in that period, according to IATA.
2. Have similar viruses spread on planes?
Yes, viruses including SARS, influenza and smallpox, which like the novel coronavirus are transmitted through the coughing, sneezing and breathing of those who are infected, have spread on aircraft. During the 2003 outbreak of SARS, which is also caused by a coronavirus, 40 flights were found to have carried probable cases of the SARS virus and resulted in spread to other passengers. Studies have found that the greatest risk comes from sitting within two rows of a contagious passenger for a flight longer than 8 hours. Still, in a case in which 20 people developed the virus from exposure to an infected passenger on an Air China flight from Hong Kong to Beijing, fewer than half were sitting within two rows of the original case. And more infections were seen in passengers sitting on the opposite side of the center aisle.
3. What can make flying risky?
People infected with the novel coronavirus emit virus-containing droplets from their noses and mouths, which can be transferred directly to someone in close proximity or by touching a contaminated surface and then the mouth, nose or eyes. What makes flying risky is the same as other forms of transport: close proximity to other people and common touch areas. The airport can also be a risk as passengers wait in queues, check in for flights, visit food vendors, and use facilities such as bathrooms.
4. What about airborne transmission?
It’s also possible that the coronavirus can be transmitted via smaller particles that people emit from their noses and mouths known as aerosols, which can float for a time through the air and be inhaled. The aerospace industry says modern aircraft ventilation should mitigate the risk of this sort of spread. The air on a plane is generally a 50-50 mix of sterile outside air and recirculated cabin air that’s been filtered. According to Airbus SE and Boeing Co., all their aircraft are fitted with HEPA filters, which capture particles as small as the virus. Airflow goes from ceiling to floor rather than front to back and is compartmentalized into sections throughout the cabin, which should limit the movement of particles along the length of the plane. Even so, modeling suggests this airflow can be influenced by factors such as seat and cabin layout and how full the aircraft is. Also, these ventilation systems may not be fully operational when planes are parked at the gate. An influenza outbreak in 1979 resulted from passengers being kept on board a grounded aircraft with the ventilation turned off. Airlines are now telling passengers to wear face masks throughout their journeys, which could reduce risks, though it’s not clear how thoroughly the rule will be enforced.
5. What else are airlines doing to mitigate risks?
Airlines are cleaning aircraft more frequently and thoroughly, and going cashless. They are using online check-in and automated bag drops. Some are no longer serving food and beverages. Passengers are being asked not to queue for the toilet and instead to press the call bell and await permission to answer nature’s call. In the U.S., JetBlue Airways Corp. and Delta Air Lines Inc. alone have promised to leave space between passengers, though other carriers are limiting the number of passengers on each flight, when possible. European airlines have largely been reluctant to commit to leaving middle seats empty, saying that the science is limited on the effectiveness of the practice and that it would make flights too costly to run.
6. What are airports doing?
In London’s Heathrow airport, Europe’s busiest, passengers and staff will be obligated to wear face masks and will see signage throughout the airport telling people to maintain a safe distance. Hand sanitizer is widely available at over 600 kiosks throughout the airport and temperature screening is being tried out. The United Nation’s International Civil Aviation Organization recently issued safe travel guidelines advising airports to go further. Recommendations include introducing contact-free technology at bag drops, boarding gates and retail outlets. The agency said a 1-meter (3-foot) distance should be maintained throughout the airport and boarding processes should be revised to avoid queuing. Bathrooms, it said, should be switched over to touch-free equipment, and dedicated baggage carousels should be in place for arrivals from high-risk areas.
The Reference Shelf
- Related QuickTakes on understanding the coronavirus, fears of second waves, lessons learned fighting the virus, the role of silent spreaders, the quest for drugs and vaccines, how the pandemic will end, the role of testing, the seasonality question, and guidance on masks.
- An IATA review of how best to restart aviation.
- An analysis of how risky flying is now from a team of researchers at Brown, Harvard and MIT universities.
- An Atlantic story on how stressful flying in the age of coronavirus can be.
- Click VRUS on the terminal for news and data on the virus and here for the latest airlines news.