Flight Frequency Regulation and its Temporal Implications

In this study, four distinct approaches for flight frequency regulation are investigated with the objective to mitigate network congestion. The approaches differ in the way how a specific number of daily flights on a route is determined: (1) directly regulating the number of flights, (2) defining an average air traffic flow management (ATFM) delay target, (3) setting a minimum acceptable schedule delay or (4) based on the marginal temporal utility of a frequency. All frequency regulation approaches are mathematically modelled, algorithmically implemented and applied to the 798 top routes by frequency in the EUROCONTROL area for the timeframe from 2020 until 2040. It is investigated that 7.6 - 22.3 million ATFM delay minutes could be avoided in 2040, depending on the chosen frequency regulation approach. This corresponds to an ATFM delay reduction of 10% - 27% by eliminating 2% - 3% of flights. The ATFM delay decrease compensates the increase in schedule delay due to fewer flight options for all approaches from 2035 onwards, conservatively assuming that ATFM delay creates twice as much temporal disutility as schedule delay. To keep seat capacity constant, airlines would have to increase average aircraft sizes considerably on frequency-reduced routes making the deployment of twin-aisle aircraft necessary. Operation-, environment-, market- and regulation-related implications are discussed