The methods and skills that are needed to land these planes at your feet are common knowledge and coached by the experienced hands. Even the most experienced, expert pilots will have an occasional landing SNAFU. I don't think the force that prevents 2 objects from slapping sides in water or air due to a pressure rise is the sole force that prolongs a Q-500s glide.....I think rising air from the hot tarmac that we typically fly over might be more intense [less diluted] at ground level. If so, this is still a ground effect, just not what the doubters here have considered.