Fakepilot
Nobody has ever been able to answer why this doesn't work. Consider: A 737 with 2 engines produces max 50K thrust. But it can lift and hold some 130K pounds. So in this case, you get 80K pounds for "free."
Try this one on for size then.
Same aircraft, rolling slowly along the ramp, with engines at idle.
Now the engines are producing almost zero thrust, yet somehow still supporting the 130K pounds.
If you can spot the error in my statement then you ought to be able to spot the error in yours.
All my life I'm taught that whenever you get an action there's a reaction, i.e. nothing's free. So I don't see how adding thrust one way gives you more than twice the thrust another way.
Thats because it doesn't.
The aircraft is being held up by a different force than the thrust. In flight, its a reaction force from the air - i.e. lift. On the ground, its a reaction force from the ground.
In both cases there are frictional forces at work that are quite a bit smaller than what is holding the aircraft up. You need enough thrust to cancel out those forces.
Hence, on the ground, a trickle of thrust is all that is required to keep the aircraft moving.
In flight, the faster speeds mean a lot of drag, so quite a bit more thrust is required. But it is still relatively small compared to aircraft weight unless you start looking at supersonic speeds.
But its the same concept in both cases.
CPB