The International Civil Aviation Organization (ICAO) mainly proposes technical and operational improvements to reduce aviation emissions.

Fuel efficiency per passenger kilometer increased by about 65% between 1960 and 2001 (with a 17% increase just in the period from 1990 to 2000). This increase in efficiency was achieved thanks to improved engine technology and aerodynamics.

Examples of operational improvements include satellite-aided navigation and air traffic control systems. The speedy introduction of systems of this kind and other operational improvements could cut overall kerosene consumption per passenger kilometer by as much as 14%.

However, three points must be noted here: the growth of aviation is so huge that it more than compensates for these increases in efficiency. Second, the potential for technical improvements decreases as time goes on because a high standard has already been attained. Third, it normally takes a very long time (15-20 years) for a technical improvement to become the standard.