Mobile phones are banned on aircraft because they can connect to, or attempt to connect to, a terrestrial network during the flight, and by doing so, start to radiate at their maximum power, exceeding levels acceptable in the aeronautical environment. Transmitting at this high power could create harmful interference to the avionics and terrestrial cellular networks.
OnAir ensures that mobile phones on board will not attempt to connect to terrestrial networks. The OnAir system creates a local GSM cell network inside the aircraft. OnAir service has received the approval of aviation authorities and over a million passengers have already flown on OnAir equipped flights.