For years, I've been told that "flyers" are caused by grass getting between the ball, causing the ball to jump out with little spin. It seems to me the grass would cause the ball to have less spin, but also less velocity. To wit, I've often wondered if in the case of a flyer, the grass suspends the ball above the ground (much like a ball in a tee) and doesn't decelerate the clubhead through impact as much as a lie on the ground. This would account for the jumping and the grass would reduce the spin resulting in a hot, lower flight. Do you know of any definitive study on flyers?