Over the past four decades, revenue passenger kilometres the volume of air passenger travel) have grown by a factor ten (see Figure of 3.1). This is "three times greater than the growth of the world's economies, which partly reflects the high income elasticity of air travel' (IATA 2011: rapid growth over the past four decades was fuelled by various factors, including globalisation, deregulation and the phased liberalisation of the air space, just-in-time inventory management, the growing middle class, increased tourism propensity, the new business-model airlines (i.e. low-cost airlines) and urbanisation (IATA 2010a: 7)
In addition, over the past four decades, the real cost of air travel has declined by some 60 per cent (see Figure 3.2), inter alia because of higher load factors the scaling of passenger flows through hub-and-spoke airlift configurations and code-share alliances, better aircraft utilisation, increased fuel efficiency linked to technological advances and vastly improved operations and infrastructure (IATA 2011: 7-9)