The relative airflow is defined as that air flow unaffected by the aircraft (or helicopter) and the angle of attack is defined as the angle between the chord line of an aerofoil and the relative airflow.

Of course the airflow is affected by the passage of the aircraft and we must consider three dimensional flow and how it changes up wash and down wash or as you would say for your helicopter rotor inflow.

The actual airflow is defined as the effective airflow and we now get an effective angle of attack, less than the angle of attack and reducing efficiency of the aerofoil section.