On the other side, aircraft ventilation systems should nullify 99% of toxic microbes from the plane's jet engines. Still, if you're sitting next to a person who's coughing or sneezing, you might be in jeopardy, because the oxygen flow on airplanes is compartmentalized. "As a rule of thumb, the air that you’re typically breathing and exposed to is usually anywhere from two to five rows surrounding your seat," Gendreau says, but leaving your vent on could create a sort of buffer zone to ward off whatever viruses might be floating around your immediate area.
Yes, the air is cold, which might prompt a shiver or two, so it might be smart to ask for a blanket. After all, the frigid air is meant for your safety as well.
[h/t Travel + Leisure]