barit1 got there first.
The lift resulting from the wing aerodynamics acts perpendicular to it. At a given angle of attack, this resultant is angled slightly backwards.
The vertical component of the resultant, in addition to the resultant vertical force of the engine thrust at a given positive angle of attack, is what keeps the aircraft aloft. The horizontal component causes a drag force, adding to the other drag forces already affecting the aircraft.
In supersonic flight shock waves form due to compressibility effects. Energy of the airflow is absorbed by these in various ways and add to the drag force.