A high‐resolution atmospheric chemistry – climate model and a mesoscale chemistry – transport model are used to provide “chemical weather” forecasts for flight planning and post‐campaign analysis. The aircraft measurements can be combined with satellite observations to provide a comprehensive understanding of the atmospheric composition. The models, that cover a wide range of space scales, assimilate meteorological (ECMWF) data to simulate realistic atmospheric conditions. Oxidation mechanisms are studied using detailed chemical models; and atmospheric air parcel transport pathways are analyzed with an algorithm that is coupled to the chemistry‐climate model. An example is shown in Figure 2.