The global distribution of air traffic at high altitudes, related fuel consumption and trends. -- Fuel consumption and emissions of air traffic. -- Hydrogen technologies for future aircraft. -- Pollutant emissions of existing and future engines for commercial aircrafts. -- Constituents and transport properties of the atmosphere above and below the tropopause. -- The atmospheric chemical effects of aircraft operations. -- Sensitivity of stratospheric ozone to present and possible future aircraft emissions. -- Possible climatic effects of contrails and additional water vapour. -- Determination of contrails from satellite data and observational results. -- An investigation of the climatic effect of contrail cirrus. -- Index of Contributors.