A method of communicating messages, the method comprising: forming an ad-hoc communication network of mobile nodes, wherein the ad-hoc communication network includes mobile nodes that are within mobile node-to-mobile node communication range of each other; communicating messages between the mobile nodes via the ad-hoc communication network using mobile node-to-mobile node communication signals; determining a path for a message through the ad-hoc communication network towards a destination node (304, 306); determining whether at least one communication gap in the message path of the network to the destination node is encountered, wherein at least one mobile node along the path to the destination node cannot pass the message on to the destination node or another mobile node, the communication gap prohibiting transmission of the message to the destination node through the ad-hoc communication network; and when at least one communication gap is encountered in the path to the destination node, the gap prohibiting transmission of the message to the destination node through the ad-hoc communication network of mobile nodes (104-1, 104-2, 104-3, 104-N), determining whether to use an alternative communication system to supplement the ad-hoc communication network based on at least a first factor selected from a set of factors including urgency of the message, whether a period of time has passed since it was determined that at least one communication gap in the path to the destination node prohibited transmission of the message through the ad-hoc network, quality of service, cost of service, class of the message, message type, message priority, required reliability, required security, acceptable transit delay, and phase of mobile node mission. forming an ad-hoc communication network of mobile nodes, wherein the ad-hoc communication network includes mobile nodes that are within mobile node-to-mobile node communication range of each other; communicating messages between the mobile nodes via the ad-hoc communication network using mobile node-to-mobile node communication signals; determining a path for a message through the ad-hoc communication network towards a destination node (304, 306); determining whether at least one communication gap in the message path of the network to the destination node is encountered, wherein at least one mobile node along the path to the destination node cannot pass the message on to the destination node or another mobile node, the communication gap prohibiting transmission of the message to the destination node through the ad-hoc communication network; and when at least one communication gap is encountered in the path to the destination node, the gap prohibiting transmission of the message to the destination node through the ad-hoc communication network of mobile nodes (104-1, 104-2, 104-3, 104-N), determining whether to use an alternative communication system to supplement the ad-hoc communication network based on at least a first factor selected from a set of factors including urgency of the message, whether a period of time has passed since it was determined that at least one communication gap in the path to the destination node prohibited transmission of the message through the ad-hoc network, quality of service, cost of service, class of the message, message type, message priority, required reliability, required security, acceptable transit delay, and phase of mobile node mission.