I recently noticed that if the climate control system is off while driving the car, there is a constant flow of air in the driver's footwell area, is that normal ? If I turn the AC or heater on, the flow of air stops in the footwell area.

 

I've noticed this too.
If you push the ari recirculate button then it goes away too.

 

Yes this is normal. The car has to breath, so they default the air to the foot well. It is the same temp as outside.
Hit the re-circ. button to shut off all air.