Airline Network Planning and Scheduling

11Basic Fleet Assignment Model (FAM)

11.1 Introduction

Most major airlines operate more than one aircraft (fleet) type. The fleet heterogeneity gives airlines the flexibility to serve markets (city‐pairs) with different characteristics related to trip distance, demand, and operations cost and revenue. For example, airlines can serve long‐haul markets using long‐range aircraft and serve short‐haul markets with short‐range aircraft. They can also serve high‐demand markets using large aircraft and serve low‐demand markets using small aircraft. It also allows airlines to adopt different strategies to strengthen its competition in the different markets. For example, an airline could decide to serve a city‐pair through scheduling a few flights using a large aircraft or scheduling frequent flights using a small aircraft. Nonetheless, fleet heterogeneity is expected to increase the operations cost of the airline as the cost elements associated with maintenance, crew training, and flight recovery during irregular operations are expected to increase (Gu et al. 1994; Subramanian et al. 1994; Hane et al. 1995; Rushmeier and Kontogiorgis 1997; Rexing et al. 2000; Sherali et al. 2006).

When airlines operate more than one aircraft fleet type, they need to decide on the most suitable fleet type for each flight. This problem is referred to as the fleet assignment problem and is applicable only to airlines that have more than one fleet type (or subfleet, derivatives of the same fleet). Figure ...