Two-way radio communications and operational transponder are normally required for operations within Class C airspace, but operations without radio communications or transponder can be conducted by LOA, facility directive, or special arrangement with Class C airspace controlling facility.

In 2026, two-way radio communication with Air Traffic Control (ATC) is a strict requirement for entering Class A, B, C, and D airspaces. Class A (generally above 18,000 feet) requires an IFR flight plan and constant contact. Class B surrounds the busiest airports and requires explicit clearance to enter. Class C and Class D surround smaller or mid-sized airports with operating control towers; for these, a pilot must establish two-way communication before entering the airspace. In contrast, Class E and Class G (uncontrolled) airspaces generally do not require communication for VFR (Visual Flight Rules) flights, though it is encouraged for safety. If your radio fails, specific "lost comms" procedures (like squawking 7600) apply. For 2026 drone pilots, entering these restricted zones often requires digital authorization through systems like LAANC, effectively acting as the "communication" link between the operator and ATC.