4 Economic measures A global, sensibly designed, market-based system for reducing emissions to complement the other three pillars 1 Technological progress Innovation in aircraft and engine technologies Alternative fuels Four pillars for climate protection [Ú 05] N 3 6 W E12 15 S 33 30 24 21 3 Operational measures More efficient aircraft sizes Optimal flight routes and speeds Optimized processes on the ground 2 Improved infrastructure Improved use of airspace Airport infrastructures adapted to needs 54 // Climate and Environmental Responsibility