For millions of Americans and millions more abroad, the excitement of booking a flight has turned into concern. Being stuffed into an airplane cabin with hundreds of other people for hours at a time seems like a risk in light of the coronavirus continuing to be a threat to public health.

According to experts, plane travel is indeed a risk, and much of that risk has to do with social proximity. But the air itself might be cleaner than you think.

In a piece for Condé Nast Traveler, author William J. McGee writes that many airplanes have highly effective air cleaning systems that use high-efficiency particulate air, or HEPA, filtration to remove 99.97 percent of airborne contaminants, including viruses. (But not all. Some regional airlines may not have HEPA devices.) The clean air is pumped in through the ceiling and leaves below the window seats. The air is roughly 60 percent fresh and 40 percent filtered and recirculated constantly.

Would this impact how coronavirus or other germs may spread? Theoretically, yes. But the Centers for Disease Control and Prevention (CDC) and other health organizations caution that no air filtration system can make up for being seated within a few feet of an infected person. It’s entirely possible that their germs will make their way to you before the circulating air removes them. And filtration isn’t a factor when travelers are standing near each other in line to board the aircraft.

Viruses aren’t the only air quality concern onboard a plane. Fumes from engine oil, hydraulic fluid, exhaust, and other sources can travel into the cabin. Pesticide applications may also leave a lingering odor.

The bottom line? If you have to be stuck in an enclosed space with several strangers, an airplane cabin might be the safest way to go about it. But variables like infected passengers, mask habits, and proximity make it impossible for anyone to offer assurances about safety. If you have a desire or need to fly, wearing a mask and keeping as much distance as possible between yourself and other passengers is the best way to approach it.

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