In this thesis research, dutch aircraft noise model (NRM) calculations are compared to measurements to analyze the aircraft classification used in the model. To do so, a new implementation of the model has been set up to calculate with LVNL trackdata and NOMOS measurement data. First, the classification approach is analyzed as prescribed, which shows clustering of aircraft types when compared to measurements. After, the theoretical input data as prescribed for the model is assessed and replaced by real data for each type specific. This leads to improvements of the model calculations when compared to measurements and shows that aircraft-specific flight-information would improve the model significantly. Concluding, it is shown that aircraft noise models strongly rely on the quality of the input data. Current input data shows certain mismatches with respect to reality, resulting in differences between calculations and measurements. However, the calculations can give valuable insights in the effect of operations on the overall noise exposure.