http://www.real-world-physics-problems.com/physics-of-skiing.html
Ski jumping

The sport of ski jumping incorporates reducing the amount of air resistance on the skier’s body as he jumps down an inclined slope in an effort in increase the distance of the jump.  Again, the crouch position accomplishes the reduction needed.  An additional way to maximize the jump distance is to minimize air resistance and maximize lift during the time the skier is airborne.  Leaning forward and making a V-shape with the skis increases the total area, creating drag as he goes thru the air.  This increases the amount of lift produced by air passing by his body as he descends; in turn, slowing his descent and allowing an increase in the distance of his jump.