fluid dynamics - Over how large an area does an airplane in flight increase the pressure on the ground underneath it?

A plane exerts downward force on the air, so the ground must exert greater upward force on the air while a plane is in flight than when it is not (in a steady state where the air has no net acceleration). This means the pressure is higher at the ground when a plane is in flight.

If a passenger jet flies several miles over me, directly above me, I don't expect to notice any change in the air pressure, even though the plane is very heavy. This suggests that the area over which pressure increases under the plane is pretty large. How large? And does it stay directly under the plane (if flying at constant speed) or lag behind?