Which airspace class typically requires a transponder for aircraft?

Class B airspace typically requires aircraft to be equipped with a transponder. This airspace encompasses the busiest airports and is designed to facilitate the safe and efficient movement of a large volume of traffic in close proximity to major airports. The requirement for a transponder, specifically one that includes altitude reporting capabilities, allows air traffic control to maintain comprehensive situational awareness of all aircraft operating within this airspace.

Transponders provide essential information, such as the aircraft’s identification, altitude, and location, helping to prevent collisions and manage air traffic flow effectively.

Class E and Class D airspace do have transponder requirements, but they are not as universally mandated as in Class B. Class G is considered uncontrolled airspace and does not require a transponder at all, making Class B the definitive choice when it comes to transponder requirements for aircraft.