An approach to the identification of the dimensions (factors) of airline services based on the stages of providing services to passengers is introduced and a loyalty measure, covering both attitudinal and behavioural aspects of loyalty, is developed and used to examine the applicability of loyalty level in determining segments in the air passenger industry. The contributions of this study to the existing literature in servicesm arketing and consumer behaviour is assessed together with the contributions made to the air passenger industry itself. The limitations of the study are discussed and the potential for future research in the area is indicated.