In actual day to day airport operations, fixed and limited resources are falling short of needs while optimization scheduling of resources is increasingly crucial and complex. In this paper, we consider the optimization problem of scheduling ferry vehicles that is one of the key supporting flows in the operation of the large hub airport. The well-known pickup and delivery problem with time windows is analyzed. And a quadratic programming model of ferry vehicle scheduling based on the objective of minimizing the variance of the number of apron flights per ferry serving is proposed. And ILOG GUROBI optimizer is used to solve the optimization model of ferry vehicle scheduling in order to obtain the reasonable gate assignment result. A case study of real-life data from our partner airport shows that optimized schedule leads to significantly better performance in comparison to intuitive and simple scheduling strategies.