By incorporating unmanned aerial vehicles (UAVs) into terrestrial system, the air-ground integrated networks are expected to take the advantage of each communication paradigm. In this letter, we consider data dissemination in air-ground integrated network that a ground base station and a UAV cooperatively serve mobile terminals (MTs). We aim to maximize the minimum received data amount of all MTs by optimizing multiuser scheduling and association, bandwidth allocation and UAV's mobility, while ensuring UAV's mobility constraints and energy budget. For the formulated mixed-integer non-convex programming, we develop an efficient cooperative data dissemination algorithm by tactfully handling the non-smooth objective function, binary variables and non-convex constraints. Moreover, simulation results show that the proposed algorithm notably outperforms benchmark schemes at different cases.