According to FOX News, typically air is cleaned during flight through high-efficiency particulate air (HEPA) filters that capture 99.97 percent of bacterial and viruses.
However, “One well-known study in 1979 found that when a plane sat three hours with its engines off and no air circulating, 72 percent of the 54 people on board got sick within two days. The flu strain they had was traced to one passenger. For that reason, the Federal Aviation Administration issued an advisory in 2003 to airlines saying that passengers should be removed from planes within 30 minutes if there’s no air circulation, but compliance isn’t mandatory.”
With fuel prices high, most airlines turn off the engines while waiting on the tarmac. When planning your next trip, consider:
– looking at however the flight is delayed
– taking an early morning flight, around 6 or 7 am, which are rarely delayed
– avoid delay prone airports, such as NYC and Chicago
If you don’t feel any air from the vents, be prepared for sickness after your flight.