The Dutch Ministry of Infrastructure and Water Management and Schiphol Airport differ on how airlines respond to a stronger differentiation of airport charges by noise category. The actual responses depend on multiple (airline-specific) factors and therefore cannot be predicted with absolute certainty. Given this uncertainty, the responses assumed by both parties are not very far apart and both seem realistic. The ratios between replacement rates for different aircraft categories used by Schiphol do seem to better reflect the savings that can be realized. It is recommended not to use separate responses for different airline segments when these cannot be well substantiated. The Ministry and Schiphol do not take into account the possibility of airlines shifting noisy aircraft from night to day or rationalizing their operations at Schiphol. As a result, the noise impact related to a stronger differentiation of airport charges is underestimated.