航班计划松弛时间是为航班地面过站设置的冗余时间，如果预留过多是对资源 的浪费，造成飞机、机组、时间等资源的闲置;但在实际运营中，又是吸收延误的重要手段， 如果预留时间过少，将造成延误传播加剧． 针对过站松弛时间优化问题，本文构建波及延 误树． 动态研究以初始航班延误为根节点触发的延误传播过程，建立航班过站松弛时间重 分配模型，该模型具有确定性和线性易于求解的优点． 通过航空公司的实际运行数据的实 验结果表明，提出的模型能够较好地解决松弛时间优化问题，在基本不改变原始的机队和 机组调度决策的基础上，不增加计划成本而将波及延误时间降低28%． 

 Slack time in flight schedule is redundancy time for flight turnaround． If slack time is too long，it is a waste of resource，such as planes，crews and time． Slack time is a significant method to absorb delay in actual operation． If it is too long， the propagated delay will be serious． A propagated delay tree with initial flight as the root was built to conduct dynamic research on the propagated process to solve the optimization of slack time． An optimization model of slack time redistribution was built，which has the advantages of certainty and linear easy to solve． Experimental results based on actual operation data of an airline show that the proposed model could reduce propagated delay by 28% without increasing costs while slightly changing the original fleet and crew schedule．