The civil aviation manufacturers need understand aviation market size and the aircraft demands in future aviation market during new aircraft feasibility study, company products strategy making and aircraft sales, which can provide the input of investment scale calculation for feasibility study, the basis for manufacture’s strategy development and data support for aircraft sales plan. The key point of forecasting future aviation revenue passenger kilometers is to forecast the revenue passenger kilometers. By linear regression to forecast aviation revenue passenger kilometers and dividing passenger aircraft loader factor, we can obtain aviation market capacities, which is called available seats kilometers, and after matching the allocation capacities of demand side and the capacities of forecast fleet, finally calculate the aircraft demand.