Abstract: A method for processing flight data having been recorded during three or more flights of an aircraft by a flight data recorder including obtaining two signature vectors with respective sizes, the two signature vectors corresponding to two different flights among the three or more flights, determining a similarity matrix, the components of which quantify the proximity between the two flight signature vectors, each component allowing identifying, for each element of a first signature, an element of the other signature which is closest, the proximity between two components of the signature vectors being a distance weighted by a mean value of the neighboring components of the similarity matrix, repeating the obtaining and determining in order to compare, two by two, all the flight signatures so as to obtain three or more similarity matrices, and processing said similarity matrices in order to evaluate the similarity between two flights.