Which of the following factors does NOT contribute to aerodynamic drag?

Aerodynamic drag is primarily influenced by factors related to how air interacts with the aircraft as it moves through it. Airflow patterns, aircraft shape, and surface texture all play critical roles in determining the amount of drag experienced by an aircraft.

Airflow patterns describe the way air moves over and around the aircraft, which directly affects drag through turbulence and the smoothness of the airflow. Aircraft shape is crucial as it can minimize resistance—streamlined shapes reduce drag whereas blunt, less aerodynamic shapes increase it. Surface texture affects how smoothly air can flow over the surface; for example, a rough surface can lead to increased friction and thus higher drag.

Altitude, however, does not directly contribute to drag in the same way. While changes in altitude affect air density and can consequently influence the performance and lift generated by the aircraft, they do not fundamentally change the factors that create drag. At higher altitudes, thinner air does lead to lower overall drag due to reduced air density, but this is not a contributing factor in the same manner as the other options. Therefore, altitude is not a direct contributor to aerodynamic drag.