“…Considering the nature of flight trajectories, the discrete Fréchet distance as defined in Eiter and Mannila (), which is a computationally efficient approximation to the Fréchet distance, is used in the present study. Following the methodology described in Mascret et al (), for a given pair of trajectories L 1 and L 2 with n and m waypoints, respectively, a Fréchet matrix M F of size n × m is computed with its element defined as follows: where 1 ≤ i ≤ n , 1 ≤ j ≤ m and d E ( L 1 ( i ), L 2 ( j )) denotes the Euclidean distance between the i th waypoint on L 1 and j th waypoint on L 2 . After iterating through all the possible combinations of i and j , the discrete Fréchet distance d Fd between L 1 and L 2 is given by the last element in M F , that is, M F ( n , m ).…”