Negative angle of attack
Is it possible to achieve flying at negative angle of attack? Let's skip the part where it would be more like fall than a flight.
Sure in theory it is not a problem. I have airfoil, I put it into a wind tunnel and I can have any aoa I want.
But in reality? Let's asume I have normal real aircraft with some normal angle of incidence. My point is that even if I nose dive the flight path vector will be always "under" the airflow. I can imagine reaching negative alpha during the pushing. For a while but once I fly down it gets and stay possitive.
Even if I look at aoa indicators they have mostly only possitive values and books or so show you lift coeficient curve but I have not seen anything which shows how alpha changes in real flight.
I know it may look simple or ridiculous but I'm really not sure.