The risk of getting coronavirus on a plane is the equivalent to the chances of “getting struck by lightning”, the airline industry says.
It comes after a US defence department study found masks greatly minimised exposure to infected air particles on a plane.
Conducted on two Boeing jets, the study found an average of 0.003 per cent of air particles around a passenger’s head were found to be infectious when a mask is worn - even when every seat is occupied.
The findings are bound to be positive news for the airline industry, which has been battered by the coronavirus crisis.
US authorities are also likely to point to the study to bolster their argument to establish safe travel corridors with countries such as the UK, with speculation that a trans-Atlantic air bridge could be set up in time for Thanksgiving on November 26.
The testing assumed only one infected person on the plane and did not simulate the effects of passenger movement around the cabin.
About 99.99 per cent of particles were filtered out of the cabin within 6 minutes due to fast air circulation, downward ventilation and the filtration systems on the aircraft.
It estimated that to become infected, a passenger would need to fly for 54 hours on a plane with an infectious person.
United Airlines, which also provided pilots for the test, took pains to present the results in its favour.
"These results ... mean your chances of Covid exposure on a United aircraft are nearly non-existent, even if your flight is full," the airline’s chief customer officer Toby Enqvist said.
The study was led and funded by a division of the US defence department, which operates flights that use commercial planes for members of the military.
The six-month research involved 300 tests during 38 hours of flight time and 45 hours of ground testing.
It was done by releasing particles the same size as the novel coronavirus across the entire cabin by section, each of which had 42 sensors representing other passengers who could potentially come in contact with the particles.
Each test released 180 million particles – the number of particles that would be produced by thousands of coughs.
Last week, plane manufacturers including Boeing released a joint publication showing that cabin air filters limit the spread of viruses on their aircraft.
Boeing’s conclusions were based on computational fluid dynamics research that simulated how particles move around aircraft cabins.
A genome sequencing analysis of a Qantas flight from Sydney to Perth on March 19 found as many as 11 passengers caught the disease over the five-hour journey.
However, almost all of the infectious passengers had disembarked a Covid-hit cruise ship earlier that day.
The International Air Transport Association (IATA) said it has identified only 44 flight-related Covid-19 cases since the beginning of 2020, from around 1.2 billion passengers who have travelled during that time.
IATA director general Alexandre de Juniac said: “Nothing is completely risk-free.
“But…the risk of contracting the virus on board appears to be in the same category as being struck by lightning.”