Because the factors affecting growth in air transportation (such as rising income and the growing share of higher-value goods demanded) are likely to continue to increase, the relative and absolute importance of aviation is expected to continue to grow too. Figs. 1 and 2 depict the historical growth in world passenger and freight aviation up to 2011 and projection by the airline industry and the International Civil Aviation Organization various years. Since 1950, global air transportation has grown at a rate of about 5% and 6% per year for passenger and freight, respectively. Most of the projection in Figs. 1 and 2 based on assumption that these historical trends will continue. For passenger travel, prior projections have been quite accurate at least until 2011, the most recent year recorded. In contrast, in airfreight, where the economy downturns caused more significant and lasting reduction in demand, long-run projections after 1990 cover a larger spreads.The dashed lines, representing a growth rate of 6% per year at difference reference years, define an envelope that includes most projections.