Boeing Corporation is raising its forecast for aircraft demand over the next two decades.

Boeing says airlines will need $4 trillion in new planes over the next 20 years.

The long-range forecast anticipates the delivery of 33,500 new planes by 2030.

The plane-maker says it raised forecasts after passenger air traffic rose eight percent in 2010 and is expected to see six percent growth in 2011.

Boeing executives are announcing the new figures ahead of next week’s Paris Air Show.