A video released by Purdue University in the US state of Indiana has revealed how viruses such as COVID-19 can spread through an aircraft cabin.
The university studied the movements of pathogens within the air conditioning system of a passenger plane and found they can travel much further than initially expected.
The video shows how saliva from just one cough causes a series of waves of germs which spread throughout the aircraft.
The animation models viruses that are airborne, but it's not yet known how airborne COVID-19 is.
A recent study carried out in the US found that one infected person passed on COVID-19 to 43 percent of their colleagues through workplace air conditioning in South Korea.
When this animation was released by Purdue University School of Mechanical Engineering in 2014, it came with a very accurate prognosis.
"Infectious diseases, such as Severe Acute Respiratory Syndrome (SARS) and avian flu, can cause significant social and economic disruption," the report said.
The model was designed to show the movement of the 2003 SARS virus, but the World Health Organisation says COVID-19 droplets are much larger so travel a shorter distance.
COVID-19 contact tracing for people on flights into New Zealand with known coronavirus cases was extended to passengers two rows in front, behind and to the side of the infected traveller.