Drag As a wing moves through the air, the airfoil is inclined to the flight direction at an angle. The angle between the chord line and the flight direction is called the angle of attack.
Angle of attack has a large effect on the drag generated by an aircraft.
The magnitude of the drag generated by an object depends on the shape of the object and how it moves through the air. As the angle increases above 5 degrees, the drag quickly rises because of increased frontal area and increased boundary layer thickness. As an object moves through the air, air molecules stick to the surface. The flow turning reacts to the boundary layer just as it would to the physical surface of the object. The separation of the boundary layer explains why aircraft wings will abruptly lose lift at high inclination to the flow.