As life slowly begins to return back to normal in a (hopefully) post-pandemic world, one of the first activities people will likely want to return to on a regular basis is traveling. Specifically, flying.

However, before you book your next flight, there is something you should now about the aircraft you’re boarding.

For 24 years Linda Ferguson worked on the cabin crew during thousands of flights on hundreds of planes, and she recently revealed to Reader’s Digest that the window seat is not all it’s cracked up to be.

Due to the great views a window seat offers to passengers, it is often considered to be the most coveted spot on an airplane.

However, Ferguson has a warning for those sitting beside a window on an airplane: Never fall asleep against the window.

The reason? Ferguson says that the window and window panel of an airplane are covered with the most amount of germs than anywhere else on the plane.

“If there was a backlight and they could light up a plane with all the germs, I think it would petrify everybody.” Ferguson said.

She recounted seeing many passengers cough, sneeze, and breathe heavily against the window. Only for another passenger to come along and lean their head against that same window later on.

But that shouldn’t force you to avoid window seats in the future. Instead of avoiding the window, it’s better to just clean up any surface you might touch by bringing your own antibacterial wipes on board.

And in some cases, germs won’t be your main concern when it comes to window seats on airplanes. The window itself is naturally a more dangerous location during flight accidents. For example, one woman died after being sucked out of a plane window that had broken mid-flight.