Reliability is a critical performance for airborn communication networks, and it is heavily influenced by network topology. Redundant designs might improve reliability, but the increased weight, cost, and complexity must be taken into account. This paper focuses on the reliabiltiy analysis of different topologies of network in airborn communication applications, and the comprehensive impact of redundancy mechanisms on its reliability performance. A network reliability simulation method based on the minimum path set algorithm and Monte Carlo simulation method is designed, and quantitative comparison and analysis of two frequently used airborn topologies and their dual redundancy forms are carried out. According to simulation results, the dual-loop topology is suitable for building the backbone network of the airborn communication system, and the dual-bus topology is suitable for some critical subnet systems with stricter reliability requirements.