A data message routing and delivery system for an air traffic control system includes a communications network with one or more ground processing nodes, one or more satellite processing nodes, and one or more avionics processing nodes each configured to send and receive data packets to and from others network processing nodes in the communications network. One or more transmission prioritizing controllers are provided to determine the locations of each of network processing node, and to control access to communication channels and routing of data messages in order of priority between the network processing nodes. An application executing on one network processing node is send to an application executing on another network processing node under the control of the transmission prioritizing controllers. The transmission prioritizing controllers determine the priority ranking of each data packet and cause each data packet to be routed over a communication channel according to its priority ranking from one network node to another until it reaches its destination.