A simple cough can project droplets into the air ranging in size. Gravity will force large droplets to the ground, but smaller droplets could stay suspended in the air for a long time. In a closed air cabin, this could increase the risk of infection for other passengers if one person is infected with the coronavirus.
Qingyan Chen and his team from Purdue University have come up with a new ventilation system for airplanes that could reduce this risk.