Close to any point on the surface of an aircraft or airfoil, the air is moving parallel to the surface; but at a great distance from the aircraft or airfoil, the movement of the air can be represented by a single vector.
The relative wind is of great importance to pilots because exceeding the critical angle of attack will result in a stall, regardless of airspeed.
As aerodynamic drag gradually overcomes this forward momentum and gravity simultaneously attracts the skydiver downward, the relative wind alters proportionally into an upward (vertical) direction.
When exiting from a forward-moving aircraft (as distinguished from a hovering aircraft, such as a balloon or a helicopter in hover mode) during a normal belly-to-earth skydive, the skydiver must arch his body in the direction of travel which is initially horizontal.
If the skydiver continues to arch, his belly will gradually alter pitch until he is belly-to-earth.