Here are the scientific reasons or proof that the virus can be transmitted via air stated in the summary:
“First superspreading events account for substantial SARS-CoV-2 transmission; indeed, such events may be the pandemic’s primary drivers.” The researchers cited choir concerts, room sizes, care homes, correctional facilities and other areas where humans interact.
“Long-range transmission of SARS-CoV-2 between people in adjacent rooms but never in each other’s presence has been documented in quarantine hotels.”
“Third, asymptomatic or presymptomatic transmission of SARS-CoV-2 from people who are not coughing or sneezing is likely to account for at least a third, and perhaps up to 59% of all transmission globally and is a key way SARS-CoV-2 has spread around the world.”