Explain · analogy
How planes stay in the air in terms of a skimming stone
A commercial flight is essentially just a very large, nervous pebble being hurled across the sky by a man in a cockpit who is terrified of gravity.
The aeroplane wing is shaped to deflect air downwards, which causes an equal and opposite upward reaction, much like how a stone skips off the surface of a pond because it is busy shoving the water out of the way. If you stopped pushing the air down, or stopped moving forward, your 747 would lose its momentum and sink into the murky depths of the atmosphere just like a pebble hitting a stagnant puddle at the local park. The engines provide the necessary thrust to keep this skipping motion going, ensuring you do not plummet while trying to enjoy a lukewarm packet of Biscoff biscuits.
You are effectively surfing a thin, invisible layer of air, relying on the fact that you are moving fast enough that the atmosphere thinks you are solid enough to skip on. It is a fragile equilibrium maintained by constant forward motion, much like a plate spinner who has to keep moving to keep everything up. If the pilot stops pushing air downwards, the party ends abruptly and you are no longer skipping, but merely falling with style towards a very hard reality.
Where the analogy breaks downA stone eventually runs out of energy and sinks, whereas a plane creates its own continuous pressure difference to stay aloft.