> Additionally, when plane speeds up, more drag is produced, slowing it down.

Wait, is it speeding up here or slowing down? Slowing down means deceleration, speeding up is acceleration, and it can't be doing both at the same time.

> When the plane slows down, it produces less drag, allowing to to pick up more speed.

Same deal?

I think what he's getting at is that drag increases with the square of speed, but it's a very confusing way of explaining it.