Flexibility in strategic flight planning

A deterministic model that indicates flexibility of flights at the strategic level (up to 6 months ahead) taking into account changing airspace configurations and capacity is formulated. Flexibility is quantified by means of time windows (TWs). Flights complying with TWs guarantee that they will not impact negatively any other flight. Three variants of the model and three types of TWs are tested on a large-size data instance (the European network for an entire day of traffic). The model output specifies the constrained flights (i.e., with TWs shorter than the maximum size allowed for their definition), the constraining sector-hours and provides a list of saturated sector-hours. The meaning of each of the results is explored, across the three TW model variants, as well as the capability of the model variants to assure that capacity limits will not be exceeded. The criticality index, a measure of the sector-hour saturation, is introduced. This index can be used to identify areas for potential improvements. Sharing the information obtained from the TW model results at a strategic level can help both airlines and air navigation service providers (ANSPs) to improve the network status: airlines can decide to re-route heavily constrained flights (e.g., with one minute wide TWs), whereas ANSPs could decide to re-organise the capacity provision of the saturated airspace portions. The TW model can be re-run with the proposed changes, with the goal to assess the impact on both the individual stakeholders and the network. Thus, the model offers the measure of flight flexibility, and can be used as a tool to assess the impact of changes, helping in decision-making processes of airlines and ANSPs.