The flying ad‐hoc network (FANET) is a self‐configured, rapidly deployable network for a variety of time‐critical applications such as military and disaster relief operations. Most mobility models view FANETs as dense networks leading to unrealistic network scenarios and may not provide real‐world results. Unmanned aerial vehicles (UAVs) may not always be connected due to low battery, malfunction, budget constraints, or the nature of the application. Existing mobility models do not work in realistic FANET scenarios, that is, sparse FANETs, and simulate the model in a two‐dimensional domain. To address the issues, a novel mobility model has been proposed for military operations in sparse FANETs. This is the first paper that addresses the issue of sparse networks as well as implementing the proposed work in the simulator in three‐dimensional space. The proposed UAV‐sink enabled mobility model (US‐MM) increases the network performance without impeding the mobility of UAVs as UAVs perform critical functions in military operations. The simulation has been done using NS‐3.25. The obtained results show the efficiency of our proposed model which achieves increased network connectivity and stability of UAV's connection to the base station in the sparse FANETs.