Capacity Constraints and Service Quality : Do Airport Slot Controls Reduce Flight Delays?

Slot controls (restrictions on the number of departing and arriving flights) are implemented at over 200 capacity constrained airports worldwide to mitigate persistent congestion and delays. However, evidence is limited regarding the effectiveness of these policies. This paper uses a quasi-experiment to evaluate whether the introduction of slot controls at John F. Kennedy (JFK) and Newark (EWR) in 2008 reduced the incidence and severity of flight delays. No evidence is found of a reduction in delays at both airports. In the months after slot controls were introduced, the average arrival delay at EWR actually increased by 7 minutes. Further, the length of Delta's departure banks (high-volume periods of departing flights) decreased by about 2 minutes at JFK while the scheduled time of EWR flights decreased by 1.52-2.24 minutes. These findings are consistent with Ater (2012), who suggested that policies aimed at reducing congestion at highly concentrated airports will only have a limited impact because dominant airlines already internalize congestion. The results highlight the need for policymakers to carefully consider how the allocation of airport slots will impact flight scheduling decisions when implementing similar policies in the future