Airports and governments pursue control of the negative externalities from aircraft opera-tions, such as noise and local air pollutants, through environmental regulations (e.g., charging or limiting). While such environmental regulations at an airport can improve the environmental performance at that airport, they may distort aircraft allocation and compromise the overall performance of the airport system. This paper proposes an approach based on environmental efficiency values measured by data envelopment analysis to assess this potential. Specifically, we estimate the environmental efficiency by employing measures of negative externalities that capture the aircraft’s performance. We then regress the efficiency values on airport characteris-tics that indicate whether the airport should be eco-efficient. We apply the proposed approach to Japanese airport data. Our results suggest that the allocation of aircraft in Japan is not distorted in terms of negative externalities and that environmental regulations at airports in Japan may be justified.