This paper investigates the formation tracking stabilization problem for fixed-wing UAVs with planar motion under a directed graph. Assuming that the constant reference position and heading is only available to a subset of followers, a specified-time distributed estimator is designed to obtain the constant configuration of the leader for each follower. Utilizing the estimated desired configuration and defined formation shape, the saturated linear speed and angular speed inputs are designed, respectively. The novelty of this paper lies in the realization of the required pose formation tracking stabilization shape under the condition that the designed linear speed remains positive for all time. Finally, the feasibility of the designed formation tracking stabilization control law is illustrated by the numerical simulation.