On which frequency do airplanes transmit?

Airplanes primarily use the aviation band frequency range of 108 MHz to 137 MHz for communication. The 108 to 117.975 MHz range is typically reserved for navigation, with the 118 MHz to 136.975 MHz frequency range used for voice communications between air traffic control and aircraft. These frequencies are modulated in AM (amplitude modulation). It is important to note that amateur radio does not have access to these frequencies as they are reserved exclusively for aviation communications.