Source: Adapted from Aviation and the Global Atmosphere. http://www.grida.no/climate/ipcc/aviation/index.htm

Trend in Aircraft Fuel Efficiency (Fuel burned per Seat)

Several factors contributed to the improvements in energy efficiency of aircraft in recent decades. The most significant (Lee et al., 2001) are:

• Improvements in engine fuel per unit of thrust: About 70%.
• Aerodynamic improvements: About 25%.
• Other factors such as economies of scale of larger aircraft:  About 5%.
• It was advocated that structural efficiency improvements, such as weight reduction, made no contribution to improved energy efficiency.

Rising energy prices have several impacts on airline companies. One involves switching to more fuel efficient aircraft.