Whats the Mechanism of flying

To achieve flight, a vehicle has to have an upwards force ( "Lift") greater than or equal to its weight.

To produce lift force, what typically happens is that air moves over a wing that is shaped in such a way so that the air moves faster over the top, and slower over the bottom of the wing. From a law of fluid dynamics (Bernoulli's Equation), if a stream of air lowers its velocity, it will have a greater pressure. This means there is more pressure on the bottom of the wing than the top, and so it pushes up on the wing, producing lift.