Picture this in your head:
I’m standing on a treadmill with rollerblades on, and I’m holding a leaf blower to represent a jet engine.
I turn the leaf blower on low, representing me taxiing to the runway, and as I start to move, the treadmill turns on, keeping me in the same location on the treadmill, so I’m not rolling off the front of it.
Then I turn the leaf blower to full power and it gives me some more thrust to get up to takeoff speed, so I get going really fast now, but the treadmill speeds up, and keeps me in the same spot.
So now I’m representing a jet engine providing maximum thrust to move me forward.
Quick, someone glue some wings to my sides.
OMG I didn’t start flying…
But wait… I found a piece of string in front of me, tied to the edge of the earth, I bet if I pull on it… YES!! I can move forward…