How COVID-19 might travel through the air?

Respiratory infections such as COVID-19 can be easily transmitted through droplets in the air. The droplets may be of different sizes. Droplets sized >5-10 μm in diameter are referred to as respiratory droplets, and when <5μm, are referred to as droplet nuclei. According to the current evidence, the COVID-19 virus is said to be primarily transmitted between people through the transmission of respiratory droplets and contact routes. 

Droplet transmission of the virus occurs when a person comes in close contact with a person with respiratory symptoms, for example coughing or sneezing. Therefore such a population is prone to having his/her mouth or eye exposed to potentially infective droplets. Transmission is also possible by exposure to the environment around the infected person. Therefore it is possible for the virus transmission to occur by direct contact with the infected person or indirect contact with the surface of the immediate environment of the infected person.

https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations