Flight explained
Why airliners cruise at around 10 km
The benefits of cruising altitude and the connections between air density, engines and weather.
At an altitude of about 9-12 kilometers, the air is thinner, so the aerodynamic drag is less and the jet can more cost-effectively maintain greater speed. At the same time, the wing still creates the necessary lifting force.
Why it is profitable to fly on the train about 10 km
The height is chosen more than once for the entire flight. The dispatcher allows the echelon taking into account the direction of movement, traffic and restrictions, and as the fuel develops, the liner can rise higher.
Much of the cloudy weather remains lower, but turbulence also occurs at the echelon. In the cabin, artificial pressure is maintained, since external pressure and oxygen for normal breathing are not enough for a person.