>The flu is much less contagious. It spreads only through droplets... Droplets also fall to the ground quicker than airborne particles

This is not confirmed. Flu is also known to spread via aersols: https://www.cidrap.umn.edu/influenza-general/study-confirms-flu-likely-spreads-aerosols-not-just-coughs-sneezes

However, flu does appear less contagious than SARS-CoV-2 but there are many possible reasons why (fewer days of infectiousness, flu is more susceptible to the body's defense, more viral load needed to induce infection, etc.)

Flu being spread mainly through "large droplets" and "large droplets" not being airborne, was the result of a medical community mistake where droplets above 5 microns were labeled as large and unlikely to remain airborne. The actual size is closer to 100 microns before a droplet readily falls out of the air. Thus many, many more droplets are actually airborne than first considered. Thus even if flu requires larger droplets it turns out those droplets can actually behavior as airborne. https://www.wnycstudios.org/podcasts/otm/segments/five-micron-mistake

Overall flu is less contagious but probably not because flu transmitting droplets are not airborne. They probably are.