Network Wide Tactical Assessment The time windows and the routes identified at the strategic level (read our insight on strategic planning) need to be validated at the tactical level, i.e. from an operational point of view. At this stage, we perform scenario simulations of the en-route phase of all flights present in a selected (large) portion of the airspace over a selected time horizon, such as one day. The input to these simulations are the planned 4-D trajectories for all considered flights obtained in the strategic planning phase and (ii) the associated Time Windows. Such data [...]