Weathervaning or weathercocking [1] is a phenomenon experienced by aircraft on the ground and rotorcraft on the ground and when hovering.
Aircraft on the ground have a natural pivoting point on a plane through the main landing gear contact points [disregarding the effects of [[toe in]]/toe out of the main gear]. As most of the side area of an aircraft will typically be behind this pivoting point, any crosswind will create a yawing moment tending to turn the nose of the aircraft into the wind.[2] [3]
It is not to be confused with directional stability, as experienced by aircraft in flight.[4]
The term also refers to a similar phenomenon in fin-guided small rockets which, when launched vertically, will tend to turn into a flight path that takes them upwind.[5]