Why Do Airplanes Need To Fly So High?

Commercial airplanes typically fly between 32,000 feet and 38,000 feet, with the sweet spot being approximately 35,000 feet. One of the main reasons commercial airplanes fly so high is air resistance. You see, the higher you go above the ground, the thinner the atmosphere becomes, and therefore, the less resistance there is to the movement of the plane. It’s pretty straightforward, actually—the more air molecules the plane must move through, the more energy it will need, so the more fuel it will need, and consequently, the operating costs will be higher.