Air band radios typically operate on VHF frequencies between 108 and 137 MHz. Sometimes spelled as airband but other term such as avionic, aviation or aircraft band radio are used because the majority of the transceivers are installed or fixed onto an aircraft’s instrument panel. Though some pilots carry a portable air band radio in their flight bag as an emergency backup or to listen to airfield activities when they’re on the ground for flight planning purposes. A multi band radio scanner can also be used to listen to air band frequencies like one featured in this video.
Some small aircraft such as microlight or gliders don’t have (or not required to have) a fixed air band radio but you will often find portable radios being used for safety reasons so the pilots can monitor nearly traffic.
Most of us would expect a modern airliner like the Airbus A380 or Boeing 787 uses some fancy digital communication devices between the flight deck and air traffic control. The reality is they all communicate using the air band frequencies listed above. In addition, most commercial aircraft have HF radio, military aircraft use UHF and both would have satellite communication facilities. The range of air band radios during cruise (30,000 ft above sea level) is around 200 miles. Remember a handheld or portable air band radio will not be able to perform this well.
A multi band handheld radio like the Yaesu VX-7R or Kenwood TH-F6 will allow the user to listen to the whole of the air band frequencies but a cheaper option would be radio scanners like the Uniden Bearcat or Maycom (I owned two of those) if you just want to listen to conversations between pilots and air traffic controllers near you. Although you can buy portable air band radios very easily, you’re not permitted to transmit on air band frequencies without a licence. The Flight Radio Telephony Operator’s Licence is required for pilots to operate radios onboard an aircraft (I got mine as part of the PPL tests many years ago) and you’ll need other types of licence, for example, if you’re a ground station operating on air band.
To summarise, air band radios are essential communication and navigation equipment used within the flying community but scanning enthusiasts and aircraft spotters often listen in on the air band activities. All operators are trained to keep their conversation brief and follow strict procedures so the next time you tune into air band, try working out if you can understand the messages. I live just outside the Heathrow air traffic zone so you can imagine how busy the radio traffic is throughout the day with thousands of flights taking off and landing.