If you mean 'how do planes fly,' I have a simple explanation for you.
Four forces act on a plane in flight. When the plane flies horizontally at a steady speed, lift from the wings exactly balances the plane's weight and the thrust exactly balances the drag. However, during takeoff, or when the plane is attempting to climb in the sky (as shown here), the thrust from the engines pushing the plane forward exceeds the drag (air resistance) pulling it back. This creates a lift force, greater than the plane's weight, which powers the plane higher into the sky.
This is a summary from the site below, which can give you much more information and examples of how planes get off the ground and are able to stay in the air and fly:
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