v (intransitive) (by analogy with the movement of a crab) To movesideways of an aircraft, such as a glider.
v (transitive) (by analogy with the movement of a crab) To navigate (an aircraft, e.g. a glider) sideways against an air current in order to maintain a straight-line course.
v (obsolete|World War I), to fly slightly off the straight-line course towards an enemy aircraft, as the machine guns on early aircraft did not allow firing through the propeller disk.