Air travel is a trying ordeal at best—long lines, cramped seats, tiny bathrooms, canned air, and everyone’s favorite part: getting sick after a flight.

But are airplanes actually dangerous to your health? Let's find out.

The Tray Table

A study from 2007 found methicillin-resistant Staphylococcus aureus (MRSA), an antibiotic-resistant bacteria, on three out of three planes tested for the "super bug." Specifically, it was found in highest concentrations on the flip-down tray table in front of each seat, with a whopping 60 percent of tray tables testing positive.

“The tray table according to our study had the highest prevalence of MRSA,” said Jonathan Sexton, research specialist at the Mel and Enid Zuckerman College of Public Health at the University of Arizona, and lead author on the study, in an interview with Healthline. “The tray tables are not commonly cleaned and get used heavily. Travelers eat and sleep on them, which allows for bacteria and viruses to transfer to the table and get passed along to the next traveler in that seat. MRSA can be isolated from many different environments so it was not surprising to find it on the plane.”

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This is a much higher rate of MRSA than in most public areas (save for hospitals). “Other studies that I have conducted found that 3 percent of personal vehicles, 3 percent of work offices, 37 percent of home offices, and 6 percent of public restrooms had MRSA,” said Sexton.

The Seat Pocket 

What’s the part of the plane that everyone touches but never gets wiped down or disinfected between flights? That handy pocket on the back of the seat in front of you and its contents.

“Surfaces that are porous retain pathogens for longer periods of time—the pocket cloth, for example, or the armrest, or the leather seats."

A new study has found that two nasty bugs, MRSA and E. coli, can live for a long time in airplane environments. The researchers tested six types of materials from airplanes (armrest, plastic tray table, metal toilet button, window shade, seat pocket cloth, and leather) by spreading the germs onto each material and then putting the samples into an environmental chamber that mimicked the pressure and humidity of an airplane.

The MRSA lasted the longest on the seat-pocket material, surviving for 168 hours, while the E. coli made it 96 hours on the armrest material.

“Surfaces that are porous retain pathogens for longer periods of time,” said Kiril Vaglenov, PhD, of Auburn University and author on the study, in an interview with Healthline. “The pocket cloth, for example, or the armrest, or the leather seats. In these little pores that bacteria find, they attach and stay safe from environmental stressors, such as low humidity, UV light, or dehydration. On top of that, when you try to clean those surfaces, the bacteria are more difficult to remove than from, say, metal toilet handles.”

Read How Holiday Travel Could Hamper Your Immune System »

Aisle Seats

Bacteria aren’t the only culprits. In 2008, a flight from Boston to Los Angeles got hit with an outbreak of norovirus, a highly contagious stomach virus characterized by causing vomiting and diarrhea. Sick passengers rushed to the bathrooms. Enough people got sick that the plane had to make an emergency landing in Chicago to get the sickest passengers to the hospital.

When the CDC followed up with passengers from the flight, they found that fliers who were seated on the aisles got sick at the highest rates. As infected passengers moved about the cabin to get to the bathrooms, they touched the seats to keep stable, spreading their germs onto surfaces that other passengers would touch.

Read About the 10 Worst Disease Outbreaks in U.S. History »

The Bathrooms

Even when norovirus isn’t infecting an airplane, the bathrooms are still disease central. Each toilet is shared among dozens of people, increasing the spread of infection. Then, many people struggle to fit their hands into the tiny sinks. Water splashes everywhere and is usually only wiped down between flights, leaving standing pools as breeding grounds for whatever the previous passenger just washed off.

“I would recommend being proactive about hygiene,” said Sexton. “Wash your hands, use hand sanitizer and avoid touching your face and high contact surfaces if possible. Allow plenty of time for traveling so you aren't rush as being rushed is an easy way to forget about the simple interventions to avoid getting sick.”

At least as of 2009, the EPA is making sure there aren’t fecal bacteria in the water supply.

The Air

One common complaint about air travel is the quality of the cabin air: sharing recycled air with a hundred other people. Surely all that time in a pressurized can breathing other people’s germy air is what gets you sick?

Actually, no.

As the plane flies, the jet engines pull in the thin cold air from the outside, compressing and heating it to make it breathable. Then, it runs through high-efficiency particulate air filters, which remove 99.97 percent of particles, including germs. Some of the existing cabin air is vented back outside, while the rest is run through the filters then mixed back in with the new, pure air. The cabin’s air is typically replaced about every two minutes. Compared with the high particle count of, say, an office building, airplane air is downright clean.

This filtration process also removes humidity from the air. If the moisture from a hundred people’s breath was allowed to accumulate in the cabin, it could affect the electronics. But this low humidity also dries out mucous membranes such as eyes and the inside of the nose. Rubbing your eyes after you’ve touched a contaminated surface is one way to catch a disease. Dehydration can also set in, weakening your immune system.

Get the Facts: Altitude Sickness on Flights »

The Food

In addition to being dry, airplane air is pressurized to an altitude of 3,000 feet or higher, which numbs your nose’s scent receptors and makes your in-flight meal seem tasteless. “This affects your whole nasal passages, much like a cold would,” said Guillaume de Syon, professor of history at Albright College, in an interview with Healthline.

The food is often minimalist to save the airlines money. “Every meal is dead weight,” said de Syon. “An extra couple of olives [are] not factored into most household [budgets]. Multiply them by, say, 20,000 in a day, and your bill just raised a few eyebrows in the comptroller's office.”

De Syon stresses that airline food is actually quite safe. “Caterers are subjected to rigorous checks,” he said. And as for the quality of the food? “We do not give a second thought when we pull into a fast-food joint, and we pay good money for something generally bad for us. Unlike standard fast food, airline meals actually have the basics for a balanced meal.”

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