47 CFR §87.89

1. (a)A station operator must hold a commercial radio operator license or permit, except as listed in paragraph (d).
2. (b)The minimum operator license or permit required for operation of each specific classification is:
3. (c)The operator of a telephony station must directly supervise and be responsible for any other person who transmits from the station, and must ensure that such communications are in accordance with the station license.
4. (d)No operator license is required to:
   1. (1)Operate an aircraft radar set, radio altimeter, transponder or other aircraft automatic radionavigation transmitter by flight personnel;
   2. (2)Test an emergency locator transmitter or a survival craft station used solely for survival purposes;
   3. (3)Operate an aeronautical enroute station which automatically transmits digital communications to aircraft stations;
   4. (4)Operate a VHF telephony transmitter providing domestic service or used on domestic flights.