Fleet Assignment with a Continuously Adjustable Flight Schedule

Fleet assignment is one of the four major steps in airline planning. The objective of the fleet assignment problem (FAP) is to determine which type of aircraft should fly on each flight leg while considering different characteristics and costs associated with different fleet types. This article proposes a multiphase approach to solving the FAP. Backward arcs were used to solve basic FAPs. Then the backward arcs were eliminated by using linear programming. By allowing backward time, our formulation has a similar level of flexibility as the fleet assignment model with time-window (FAMTW), but the problem size grows much slower than FAMTW. Examples using real data obtained from a major airline are included in this article.