Modern air traffic management relies on a communication infrastructure increasingly suffering from the VHF band’s growing saturation in high density areas. Air traffic management communication shall therefore transition from analog VHF voice communication to more spectrum efficient digital data communication. These proposed digital technologies have to be evaluated carefully against the expected data traffic to ascertain that they offer the required capacity and performance. This paper describes the characteristics of air traffic management data and a method to generate a data traffic pattern suitable as input for the performance evaluation of digital aeronautical data communication systems. The data traffic pattern is derived from large scale computer simulations. Based on the simulation results, the paper provides guidance on how to model a data traffic pattern that is directly usable for practitioners wishing to evaluate the performance of aeronautical data communication systems.