I am happy to solve this problem for you, in fact, the aircraft, especially military aircraft communication methods are varied, if the original means of communication, when flying across the border, in our native high-frequency radar can be detected in the range can be used in ultra-short-wave and microwave communications, do not need to be a repeater directly and the native navigation station contact. If flying over the horizon, our local radar can not be detected, that is, straight-line communication can not be used, you can switch to short-wave communication, short-wave communication in the ionosphere has a reflective effect, can make the ionosphere will reflect the aircraft's short-wave signals to the mainland, received by the receiving station and forwarded to the airspace center. Due to the narrow bandwidth of short-wave communication, the transmission is not stable, and there are obstacles to the transmission of large data. It is also possible for our bases outside China to act as relay stations and relay the signals back to China via satellite. There is another way is through the command aircraft equipped with satellite communication antennae will be sent directly to the satellite cluster of signals forwarded to the domestic. Theoretically, all the bands after the ultra-short wave are straight line propagation, so within the line of sight as long as the power allows, hundreds of millions of kilometers are possible, as long as the transmitter power is large enough. But after flying over the horizon, it will enter the blind zone. Need to relay or switch to short-wave, short-wave as long as the power of one watt is possible and the American continent radio stations to get connected, mainly depending on the weather, depending on the state of the ionosphere.