1. A computer system comprising one or more processors and/or transceivers configured to: retrieve (i) a forward-link user capacity matrix comprising a plurality of forward-link user capacity estimates, each of which is associated with a respective location on the ground; and (ii) a return-link user capacity matrix comprising a plurality of return-link user capacity estimates, each of which is associated with a respective azimuth and a respective elevation with respect to a current location of an airborne aircraft; determine, based on forward-link user capacity matrix and the return-link user capacity matrix, a candidate serving cell that is disposed on the ground; and command a directional antenna and a particular transceiver to transmit or receive data between the airborne aircraft and the candidate serving cell.