It's dry up there: drink water when flying
The next time you fly, soak a terrycloth hand towel so that it’s dripping wet and hang it up on the flight deck.

The next time you fly, soak a terrycloth hand towel so that it’s dripping wet and hang it up on the flight deck. Then fly a leg that’s at least an hour-and-a-half long. At the end of that time, the towel will be bone dry, the water absorbed by the ultra-low humidity of the cockpit and cabin environment.

Now just think of what that environment is doing to your body. And, in an even more profound and perverse way, to your mind and your ability to make the judgments needed to fly an airplane.