No One Can Explain Why Planes Stay in the Air
scientificamerican.com
scientificamerican.com
The title sounds a little cringeworthy to me because it sounds like it is about the fake controversy about the Bernoulli Principle.
The Bernoulli Principle doesn't explain lift from aircraft wings at all (particularly in that the 'angle-of-attack' is so critical to lift) and all reference to it should have been excised circa 1960 but oddly it has survived in this narrative that there are two competing theories about lift that has chronically survived in places like the manual for the 1980 Microsoft Flight Simulator.
The angle of attack is always measured relative to the airflow, whether that relative airflow is upwards or downwards or sideways.
Note that at zero degrees of angle of attack, the wing still provides 'lift' due to the Bernoulli Principle. At negative degrees angle of attack, the wing moves 'downwards' relative to the airflow, when the angle of attack is positive the wing moves 'upwards' relative to the airflow. NOTE: the terms 'upwards' and 'downwards' here are directions relative to the aerofoil/wing and have nothing at all with the orientation of the wing to the ground. (If a plane is flying upside-down, 'downwards relative to the wing' would lead to an increase in the plane's altitude.)
When the angle of attack exceeds roughly 15 degrees relative to the airflow the fluid ('air', in other words) becomes turbulent which destroys the 'lift' and the wing is said to be 'stalled'. Being stalled is a dangerous situation and leads to aircraft literally falling out of the sky.