Which color is used to depict airports with control towers in Class B, C, D, and E airspace on Sectional Aeronautical Charts?

On Sectional Aeronautical Charts, airports with control towers in Class B, C, D, and E airspace are depicted using the color blue. This color designation is used to visually distinguish controlled airports from uncontrolled ones, which are typically shown in magenta. The blue color not only indicates the presence of a control tower but also signals to pilots that there are specific operational procedures and traffic patterns that are in effect at these locations. This helps in ensuring safe and efficient air traffic management around airports where air traffic control is provided.