The explanation of the principle of airplane lift is one of the hottest topics in science; how exactly does lift in an object develop?

To fly is to resist gravity and "float" in the air. There are many ways to resist gravity.

1. First Universal Velocity

If you fly fast enough, you can resist gravity. How fast do you fly? Near the ground, the first cosmic speed was reached, which is 7.9km/s, almost more than Mach 20.

It can't be done. We can't achieve that speed in the air because the drag would be very high, and it would generate extremely high temperatures.

2. Lighter than air

By making a vehicle lighter than air, it can be held up by the buoyancy of the air; hot air balloons and helium blimps are in this category.

They can hover still in the air and are very environmentally friendly, with the disadvantage of being too large and having low speeds.

3. Principle of Wing Lift

The wing lift is primarily attributed to two key factors: Bernoulli's principle and Newton's third law of motion.

When air flows over an airplane wing, it is split into two different streams: the upper stream that moves over the curved upper surface of the wing and the lower stream that passes underneath the wing.

The upper surface of the wing is usually curved. In contrast, the lower surface is relatively flat—this difference in curvature results in a variation in the speed of the airflow over the wing.

The curved shape of the wing's upper surface causes the air traveling over it to accelerate, thus producing a lower pressure compared to the air below the wing.

This lower pressure creates a pressure gradient between the upper and lower surfaces of the wing. According to Bernoulli's principle, the higher pressure beneath the wing pushes the airplane upward, creating lift.

Additionally, Newton's third law of motion plays a role in generating wing lift.

The wing, as it moves through the air, exerts a downward force on the air particles (action), and in response, the air exerts an equal and opposite force upward on the wing (reaction) according to Newton's third law.

This upward force is the lift that counteracts the aircraft's weight, allowing it to stay aloft.

4. Special flights

There are also very small or light things that seem to "float" in the air—for example, willow flakes, dandelion seeds, haze, and so on.

All of these things are heavier than air, and they will eventually fall back to the ground. It's just that they fall so slowly that it's like they're floating all the time.

When the size is very small, the drag created by the viscosity of the air can be so significant that the air resistance is already equal to its weight. They fall at a very slow and even rate, and with a slight updraft, they are up again.