Planning to fly home after the Thanksgiving holiday? Be aware that cold and flu outbreaks typically soar in winter months, in part because of germs spread by dirty surfaces on airplanes and in airports.

To help travelers reduce their risks of catching a cold, the flu, or other infections, Travelmath.com has ranked the dirtiest places in airports and airplanes, based on samples gathered by a microbiologist who examine airports and plane flights.

The Website, which helps people calculate the driving and flying time between cities, found airports and planes tend to be dirtier than the average American home. But the places where they found the most germs might surprise you.

For instance, the samples gathered show that bathrooms in airplanes and airports have fewer germs than other areas you might not consider hotbeds of infectious pathogens.
“Bathrooms were some of the cleaner surfaces tested, which may be contrary to conventional thought,” the researchers reported. “Regular cleaning schedules mean these surfaces are sanitized more frequently. This is a good thing.”

By contrast, the tests showed the dirtiest place on most planes is the tray table — the surface most travelers will touch as they eat and drink in-flight foods and beverages.

Researchers found that the tray table had 2,155 "colony forming units" — a measure of the number of bacteria or fungal cells that are able to multiply — per square inch. That compares to just 265 CFU on the lavatory flush button, 285 CFU on the overhead air vent, and 230 CFU on the seat belt buckle.

In airports, the findings were comparable, with tests showing that drinking fountain buttons had 1,240 colony forming units per square inch, compared to only 70 CFU on bathroom stall locks.

Here is Travelmath.com’s ranking of the dirtiest places on airplanes and in airports that you should try to avoid:

No 1. Tray table: 2,155 CFU.

No. 2. Drinking fountain buttons: 1,240 CFU.

No. 3. Overhead air vent: 285 CFU.

No. 4. Lavatory flush button: 265 CFU.

No. 5. Seatbelt buckle: 230 CFU.

No. 6. Bathroom stall locks: 70 CFU.

According to research by the National Sanitation Foundation, some of these airplane and airport surfaces have higher concentrations of microbes than while household toilet seats, cell phones, and even money. Still, some surfaces in the home — including pet bowls (306,000 CFU), pet toys (19,000 CFU) and kitchen countertops (361 CFU) — can pose a greater risk.

The Travelmath.com researchers noted that while it might seem counter-intuitive that bathrooms are cleaner than tray tables and countertops, the tests suggest airlines and airports are sanitizing rest rooms, which can easily spread disease if not cleaned properly.

“The bad news is that airlines and airports don't appear to be doing a good enough job of cleaning other things,” the researchers noted. “Travelmath points out that the pressure on airlines to board a plane quickly has increased in recent decades, meaning tray tables often don't get cleaned until the end of the day.”

To reduce your risk of picking up a nasty bug, experts advise:

•    Avoid eating anything that comes in contact with your tray table.
•    Wash your hands frequently while traveling.
•    Carry portable hand sanitizers and use them often.