An air interface for a terrestrial communications network for providing broadband internet access to aerial platforms is described. In some embodiments, systems and methods are described for efficient retransmission of data packets that are not received correctly. In other embodiments, systems and methods are described for determining the modulation constellation and error correction code rate used in transmitting a data packet to maximize data rates. In another set of embodiments, the retransmission scheme and modulation constellation and error correction code rate determination are jointly optimized to maximize data rates.