This makes tourism a co-ordination-intensive, as well as information-intensive, industry (Zhang et al. The key components of tourism are accommodation, transport, attractions and excursions, and restaurants; all are ‘perishable’. This means that airline seats, hotel rooms and daily ticket sales, for example, cannot be stored for potential future sales. This level of uncertainty, coupled with the uncertainty of global trends and exogenous shocks, has become an important area of tourism supply chain research. Areas of particular interest include demand forecasting, yield or revenue management and inventory management (Zhang et al. Finally, the supply chains in tourism that already exist are usually part of the wider global operations of major hotels and resorts (for example Hilton and Four Seasons hotels) and of cruise ship operators (for example Carnival Corporation and Royal Caribbean).