A method for modeling aircraft performance including (a) introducing aircraft degradation coefficients in a nominal aircraft performance model of an aircraft and obtaining a degraded aircraft performance model, (b) calculating computed trajectory data in a trajectory computation infrastructure using as inputs aircraft intent which represents trajectory data, weather data, and the degraded aircraft performance model; (c) comparing the trajectory data with the computed trajectory data; (d) obtaining an enhanced aircraft performance model by considering the degraded aircraft performance model as the enhanced aircraft performance model, when the result of the comparison is less than a previously established threshold; and (e) modifying, when the result of the comparison is higher than the previously established threshold, the aircraft degradation coefficients and executing steps (a) to (e) of the method, until the result of the comparison is less than the previously established threshold.