Sarkus; In the video I watched a pickup pull a portable 'runway' in the -x direction while a pilot flew his small 'cub' class plane off the 'runway' in the +x direction. Takeoff speed would have been approx. 50 mph. It is a real world demonstration that it can be done, and without any sophisticated high tech preparation. Whatever the source of the mental block, lack of in depth analysis, fixation on one factor over all others, etc., seeing is believing. It isn't necessary to remove friction, and it's needed if the pilot wants to apply brakes. My error is to visualize the typical conveyor operation of moving material, which is held in place by friction. If a small cylinder is placed on a sheet of paper, and the paper is slowly pulled in the -x direction, the cylinder, having near zero contact with the paper, will acquire a small torque around its center, causing it to roll in the +direction, contrary to typical conveyor operation. The wheel is the cylinder in the airplane case and it is rotating in the +x direction. The motion of a conveyor belt can only increase its rotation rate via friction. Yes these factors were mentioned, but understanding comes when you can explain it to yourself.