I don't think the explanation is very difficult to understand, but it is not so intuitive as to know without knowing the theory, so there are mainly two reasons.
The least important reason is (or are) the engines, which push the plane forward allowing the wings to fulfill their function.
The other reason, the most important one, is the wings, whose operation is quite curious, and allows the plane to stay in the air despite its enormous mass, and this is achieved thanks to the shapes of the wings.
To explain this, let us suppose that the air travels in a group, as if it were a gang of friends, and that when it hits the front part of the wing the group divides, but they have to meet at the end of the wing at exactly the same moment, without doing anything. wait for no one
In this way, as the upper part of the wing is curved and the lower part is much straighter, the group that has gone above will have to run further to meet their friends at the exact moment in which they have agreed to meet again.
This is how an enormous upward thrust force is generated, since the air that moves at higher speed generates a pressure very lower compared to that generated by the air below. This thrust force is enough to keep the plane in suspension, and even depending on the orientation of the wings, it is enough to lift the plane.
The function of the engines is to propel the plane forward to generate much greater differences in air speed between the bottom and top of the wing, thus achieving even more thrust force.
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