What is the call sign for Delta Airlines?

Delta Airlines uses the call sign "Delta" when communicating in air traffic control and other operational contexts. This call sign is a unique identifier that helps ensure clear and efficient communication between the airline's aircraft and air traffic controllers. It is derived from the name of the airline, which helps to avoid confusion with other airlines and is consistent with aviation communication conventions where carriers often use their names for identification.

The other options listed are associated with different airlines, making them irrelevant to Delta Airlines’ operations. "American" is the call sign for American Airlines, "Brickyard" is the call sign for Republic Airways, and "United" refers to United Airlines. Recognizing these specific call signs is important for pilots and air traffic controllers to maintain safety and order in the airspace system.