If you’re one of the millions of people traveling by plane for the holidays, you’re probably aware that planes are a perfect environment for germs to spread. It’s why vitamin C boosters are so popular with travelers. But just where exactly will you encounter the most germs while flying?

“I think of airplanes as emergency rooms in the air,” Jason Tetro, microbiologist and author of “The Germ Code,” told Yahoo Life.

“You are surrounded by people you don’t know, and their health status is completely unknown. And if there hasn’t been a good cleaning and disinfection, you have no idea about the people who were on the plane before you,” explained Tetro.

While airlines clean their aircraft between flights, it’s not a practice enforced or regulated by the Federal Aviation Administration.

Andrea Sachs —a travel reporter with the Washington Post — did her own research on the cleanliness of plans by using an inspector kit AAA uses for hotels. Her amateur research revealed these are the five of the germiest places on a plane:

  • Bathroom sink handle
  • Tray table
  • Inside bathroom door handle
  • Seat belt buckle
  • Armrest

“A 2019 peer-reviewed study by the Hunter College NYC Food Policy Center at the City University of New York showed the drinking water on planes as potentially unsafe for humans. The study scored 10 major airlines from 0 to 5 and found that seven out of 10 scored a three or below,” added Travel + Leisure.

While the dirtiest places on a plane are all items that are often touched, Josephine Remo, a flight attendant and travel blogger, shared that the dirtiest spot on a plane — for her, at least — is the safety instruction card in the seat pocket as it never gets cleaned or wiped down.

Avoiding germs while flying may seem impossible, but health professionals, flight attendants and travel bloggers all say the same thing: Bring disinfecting wipes and hand sanitizer.

“Before you sit down and buckle up, use a disinfectant wipe. Clean your seat, seat belt, armrest, and tray table, all of which contain germs. If you need to adjust your overhead light or air vent, use hand sanitizer afterward. The same applies if you touch anything in your seat back pocket,” advised Family Doctor.