Airborne planes can easily be heard from well over 100 miles, so you don't have to live near an airport. If you do live near an airport, you can find out all the traffic control, weather, and Traffic Advisory frequencies by entering the airport at AirNav.
At most small airports that don't have control towers, the UNICOM frequency is used by the pilots use to talk to each other, usually 122.700, 122.800, 122.900, 123.000 or 123.050. Airports with control towers usually have an assigned Unicom channel of 122.950. Most airports large enough to have control towers have the following types of channels:
ATIS (Automatic Terminal Information Service)- Weather, equipment failures, closed runways and taxiways, current operating runways, special notes, and NOTAM's.
Clearance Delivery - The pilot uses this frequency to notify a controller of his flight intentions and to receive flight instructions and clearance for take-off.
Ground Control - The ground controller tells the pilot which taxiways to use to arrive at the correct runway.
Tower - The Tower Controller is responsible for the aircraft in the immediate area around the airport (Up to 3000 feet and 5 miles from the airport). Once the aircraft leaves the airspace of the airport, the pilot will be handed off to a controller at a TRACON (Terminal Radar Approach Control) or an ARTCC Center (Air Route Traffic Control Centers), commonly called Air Traffic Control).
Approach Control (TRACON) - Directs several lines of descending aircraft into one smooth flowing line of aircraft as their courses take them closer to the destination airport.
Departure Control (TRACON) - Routes air traffic immediately upon takeoff via a preferential departure route (PDR) leading away from the departure airport as the aircraft ascends to the en route phase of flight.
Aviation radio frequencies are found in the low frequency (LF), medium frequency (MF), high frequency (HF), and very high frequency (VHF) bands. These frequencies may be used for voice communications or for navigation.
Historically, when aviation radio was first starting out, most air navigation transmissions took place on the low frequency band from 200 KHz to 415 KHz. As reliable higher frequency systems were developed, most of the low frequency air nav beacons were shut down. Today, some low frequency beacons remain and are used for instrument landings. Others were kept operational as backups in case of primary navigation system failures. Low frequency is useful even when other forms of communication fail because its long wavelengths are less affected by terrain and it can bounce off the ionosphere to travel long distances around the world.
Aviation radio is allocated a small portion of the medium frequency spectrum in a band from 2850 to 3000 KHz. Most planes have radio direction finders onboard that get a bearing by focusing in on a medium frequency transmission.
In the past, high frequency bands were typically used for domestic voice communications. That traffic has since shifted to the very high frequency (VHF) band. High frequency continues to be used for voice communications for international flights, however, as it can travel a longer distance than VHF.
Frequencies in the very high frequency band are most widely used for domestic aircraft communications at the present time. Both communication and VOR navigational systems are operated on VHF frequencies.
To support full VHF communications, the FAA recommends that all aircraft with older 360-channel systems should be retrofitted with a 760-channel piece of equipment with 25 kHz channel spacing which is capable of operating in the 118.000 to 136.975 MHz band.
118.000 - 121.950 Air Traffic Control (See AirNav)
121.975 - 123.650 Unicom, multicom, Flight Services, Traffic Advisory (CTAF) at uncontrolled airports
123.675 - 128.800 Air Traffic Control (See AirNav)
128.825 - 132.000 Company Airlines Operational Control
132.025 - 136.475 Air Traffic Control (See AirNav)
136.500 - 136.975 Company Airlines Operational Control
More specific info can be found at: Aircraft Frequencies
(See Note 1)
121.5000 Civilian Guard
243.0000 Military Guard
Some of the more popular:
123.4500 Itinerant channel
122.7500 Fixed Wing