How do planes get used to the sky?

The speed of the plane is provided by the engine. The principle of the engine is that air is sucked in by the fan in the air inlet, then compressed to high pressure by the compressor step by step, and supplied to the combustion chamber, and mixed with the fuel tank to produce high-temperature and high-pressure gas, which is supercharged by the turbine behind the combustion chamber in multiple stages, and finally ejected from the tail nozzle at high speed, resulting in huge reverse thrust. This is the driving force of the plane. Thrust produces speed. The lift is provided by the big wing. The wing is not a simple piece, its shape is that the upper surface is convex and the lower surface is flat. According to the fluid continuity theorem, if a pipe is divided into Y-shaped bifurcations, assuming that the upper two bifurcations are thick and thin, then the fluid mass of the liquid flowing from the bottom is the same in unit time, then obviously, the liquid on the thin side will flow faster. This is the fluid continuity theorem. Similarly, because the upper surface of the wing is convex, the distance that air flows through the upper surface is longer than that of the lower surface. According to the fluid continuity theorem, the air velocity on the upper surface will be faster. According to Bernoulli's theorem in fluid mechanics, the air on the upper surface will produce less pressure on the wing, and the direction of this pressure is downward, but the pressure on the wing from the air on the lower surface is upward, which is greater than the pressure on the upper surface, so the resultant force of the two pressures is upward, which is the source of aircraft lift. This lift is proportional to the speed of air relative to the wing, that is, to the speed of the aircraft. With these, it can be explained. When the plane took off, the throttle began to accelerate at one end of the runway. The higher the speed, the greater the lift. When the takeoff speed is reached, the lift is enough to make the plane fly, and the plane can take off with its head held high. In the air, of course, the engine jet provides thrust to maintain speed, and then maintains lift to ensure that the plane will not fall.