International audienceIn an airplane preliminary design phase, the optimization for costs and fuel consumption is based on anticipating the future operations of the airplane by defining one representative mission. How effective is this process? In this study, based on data exploration and statistical analysis, we identify and represent the operational parameters impacting the variability of the actual missions of an airplane. These parameters include the airline route network and flight optimization, Air Traffic Management (ATM) considerations, and the atmospheric and meteorological phenomena. Our results show how significant some impacts are, mainly on actual flight distances but also on flying conditions. A conclusion of our study is that airplanes are operated on missions different from the reference mission considered during the preliminary design phase and this has a significant impact on operating costs and fuel burn efficiency