Over 1.5 litres of your body’s water is lost each long-haul flight
Flightbuddy - Interesting facts about aviation It's scientifically proven that you lose around 4% of your body water when you fly for 10 or more hours! Women lose an average of 1.6 litres of water, and men 2 litres. This is a result of the cabin's lack of humidity (it's drier than the Sahara desert!) and oxygen-thin air. So remember to drink lots of water when flying!