The Airline Fleet-related Implications of a Utility-based Frequency Limit between High-DensityCity Pairs in Europe

To overcome airport and airspace congestion the amount of aircraft movements needs to be managed. However, even with slot limits in place at most major European airports congestion persists, particularly at airline hubs. In this study the amount of flight frequencies between individual city pairs as a target value to be regulated is investigated. For that purpose a welfare-oriented metric to measure the utility of frequencies between city pairs is developed. The metric is based on an econometric model that incorporates the trade-off between schedule delay and ATFM delay. Whereas schedule delay is modeled analytically, ATFM delay is calculated deterministically via non-linear regression of empirical data. After transformation this approach enables to determine the optimum amount of frequencies between a city pair as a function of the passenger demand. Its application to high-density connections from major European airline hubs shows that during the summer many cities are served with non-optimal amounts of frequencies. If a demand-dependent frequency limit based on this approach was introduced airlines would have to reduce frequencies substantially and operate twin-aisle aircraft on short ranges to accommodate the same amount of passengers. Further research of this topic requires an overall systems-perspective to account for the concerns of all involved stakeholders.