In this paper, a new network topology control mechanism is proposed to improve routing path duration in Aeronautical ad hoc network, which can effectively decrease the probability of routing path breaks in the process of nodes high-speed moving, and be integrated with existing routing protocols used in Adhoc network smoothly. The main principle of topology control mechanism is according to the different node densities with different topology construction method. For network regions having a high density of aircraft, the packets are preferentially routed over the long available links created by the aircraft moving in same direction.
For low density of aircraft, the routing preferentially uses the short available links created by the aircraft moving in both directions. This mechanism can increase the routing path duration effectively. We combine the topology control mechanism with OLSR, and give the Path Link Availability Routing Protocol (PLAR). We compare the performance of PLAR protocol with other routing protocols in different scenes. Experimental results show that, PLAR protocol exhibits a significant improvement over most routing protocols base on topology and position.