The number and diversity of space and higher-airspace missions is rapidly growing worldwide, including Europe. However, the prosperity of these new entrants may become incompatible with that of the conventional aviation, unless their coexistence is regulated. Since “what gets measured gets managed”, the impact on the conventional air traffic needs to be evaluated. To that end, we conduct a literature review and propose a methodology to quantify the impact that a real, segregated, special operation within a vertically unlimited volume had on regular air traffic. This methodology is then applied to a recent disruptive event in southern Europe.