While the proportion of aviation CO2 emissions may be comparably low, the contribution to radiative forcing effect (global warming) is not negligible. The report of the Intergovernmental Panel on Climate Change estimated that this effect could be two to four times greater than that from aviation CO2 emissions alone (IPCC, 1999). Analyses have shown that greater reductions in CO2 emissions can be achieved more efficiently in other sectors. However, the transport sector should contribute to achieving EU targets under the Kyoto protocol. The EU has set a target of 60% reduction in the transport sector by 2050 with respect to 1990 levels (EC, 2011c). However, the expected increase in air traffic poses significant challenges in reducing CO2 emissions to meet this target. Emission reduction will have to be achieved by improving the efficiency of aircraft engines and aero-structures, developing new and innovative technologies, use of alternative sustainable fuels for aviation, and by implementing future-oriented operational procedures such as the Single European Sky.