Deflection is a technique used for effectively propelling a projectile at a moving target, also known as "leading the target", i.e. shooting ahead of a moving target so that the target and projectile will collide. This technique is only necessary when the target will have moved a sufficient distance to fully displace its position during the time the projectile would take to reach the target's range. This can become the case over long distances (e.g. a distant target for a skilled sniper), due to fast moving targets (e.g. an opposing aircraft in an aerial
dogfight), or while using relatively slow projectiles (e.g. a
crossbow bolt or a basketball thrown to a running teammate). During
World War II,
U.S. Navy pilots were taught explicitly about the concept in order to capitalize on the advantages of the
F4F Wildcat.