For the problem of communication support for the mission of aircraft formation, the connectivity of the network is ensured by way of adding relay nodes according to the characteristics of airborne hierarchical network. A relay route planning method for connectivity of airborne hierarchical network is presented. Taking aircraft mission routes as input, the method optimizes the spanning tree by comparing whether the connected component of the vertex of the edge in minimum spanning tree (MST) is the same as the previous time. The relay segment vectors are connected with the degree of the vertex of the relay segment vectors and the motion time of the relay nodes between two relay segment vectors as the joint weight. Simulation demonstrates that the proposed method can achieve the reuse of relay nodes in time and space. Compared with the traditional algorithm, the method can effectively reduce the number of relay nodes, and achieve the optimization of relay node routes.