Related by context. Frequent words. (Click for all words.) 45 Fuel Efficiency 42 Volvo Aero 41 ACEA 41 reducing CO2 emissions 40 C# emissions 39 zero emission 39 EWEA 39 reducing carbon emissions 38 greenhouse gas GHG 38 Emissions 38 CO2 emissions 38 National Airspace System 38 Hydrogen 37 greenhouse gas emission reductions 37 Alternative Fuels 37 Environment Commissioner Stavros 37 nitrogen oxide emissions 37 greenhouse emissions 36 NOx emissions 36 alternative fuels 36 FDF 36 emissions 36 IAE 36 cleaner fuels 36 CO2 emission 35 renewable energies 35 renewable fuels 35 Aeronautics 35 nitrogen oxides NOx 35 Renewables 35 FFVs 35 NEDC 35 GHG reduction 35 efficiency 35 emission 35 Carbon Emissions 35 particulate emissions 34 carbon dioxide emissions 34 reduce carbon emissions 34 pollutant emissions 34 exhaust emissions 34 carbon dioxide emission 34 Eleventh Plan 34 carbon emissions 33 NOx 33 hybrid electric 33 Millennium Development Goals 33 Global Warming Solutions 33 biofuels 33 greenhouse gas emission 33 particulate matter PM 33 Co2 33 nitrogen oxide 33 hydrogen powered 33 greenhouse gas emissions 33 Turbomeca 32 carbon emission 32 EBIT margin 32 greenhouse gas GHG emissions 32 achievable 32 PHEVs 32 nitrous oxide emissions 32 hydrogen fuel 32 CO2 32 renewables 32 reduce greenhouse gas 32 emission reductions 32 tailpipe emissions 32 PlaNYC 32 Unmanned Aircraft Systems 32 GE Aviation 32 EVs 32 EADS 32 Clear Skies 32 carbon emitting 32 Pickens Plan 32 renewable energy 31 cleaner greener 31 Carbon dioxide emissions 31 EU Emissions Trading 31 carbon dioxide CO2 emissions 31 Greenhouse Gas Emissions 31 Renewable Energy 31 technologically feasible 31 rotorcraft 31 biomethane 31 Electric Vehicle 31 Millennium Goals 31 Astrium 31 CAFE standards 31 Energy Efficiency 31 Renewable Portfolio Standard 31 composite materials 31 Aircraft 31 reducing greenhouse gas 31 emission reduction 31 Low Carbon 31 greenhouse gases 31 Propulsion 30 aerostructures 30 Greenhouse Gas