If planes fly at such high altitudes, it is for several reasons that we do not think about.
Seen from the ground, planes appear so small, sometimes even barely visible, they are so high. If we can guess why the devices don’t fly at low altitude, it’s difficult to be certain of the reasons that make them fly several thousand meters above the ground. But first of all, precisely how high do planes fly? As for commercial flights, their altitude varies between 17,000 and 40,000 feet, which corresponds to a scale of 5100 to 12,200 meters above sea level. For their part, private jets can go even further higher, up to 51,000 feet, or 15,500 meters.
Planes therefore fly up to 15 km above our heads, for several reasons: some are linked to physics, others to aerodynamics, but also to fuel economy and safety. This high flight altitude is the result of careful optimization to ensure safe, efficient and comfortable travel.
The first explanation is aerodynamic: at high altitudes, the air is less dense, meaning there is less resistance to the plane’s forward motion. Airplanes are designed to maximize their aerodynamic efficiency in these conditions. At lower altitudes, denser air would increase drag and require more power to maintain cruising speed.
But what explains the height of airplane flights is also linked to fuel consumption and its economy. Indeed, flying at high altitude allows planes to reduce their consumption. At these altitudes, fuel consumption per unit distance traveled is reduced due to reduced air resistance. This makes travel more profitable for airlines, resulting in lower operating costs and potentially more affordable fares for passengers.
Flying at high altitude is also a safety condition. At these altitudes, the aircraft has greater room to maneuver in an emergency. It is easier to avoid obstacles such as mountains, buildings or bad weather. Additionally, planes flying at high altitudes are generally less prone to turbulence, thereby improving passenger comfort. This helps minimize the risk of collision and ensures flight safety.
