Airplanes need to have airbrakes and wheel brakes.
Currently reducing thrust to 0 slows the plane down, however pitching down even five degrease causes the plane to speed up. We need air brake to be able to slow down the planes.
We need wheel breaks to stop the plane on the ground. Currently the only way to do so is by reducing the throttle to 0 or pressing Z.
Z seems to be the ultimate break. However, reducing the thrust to 0 should not act as a break, the plane should glide if in the air and roll if on the ground.
Hope this makes sense.