A method for determining diversion trajectories for an aircraft relative to a main trajectory defined for the aircraft in an environment, the method being implemented by an electronic installation, the method comprising a preparation phase comprising the following steps: a. obtaining an image of the environment intended to be overflown by the aircraft between a departure point and an arrival point, a representation of the following elements having been added to the image: i. a main trajectory intended to be travelled by the aircraft between the departure point and the arrival point, ii. at least one point of diversion of the aircraft away from the main trajectory, each point of diversion being a point in the environment away from the main trajectory and giving access to a safety zone, a safety zone being a zone away from a potential danger identified along the main trajectory, b. meshing the image into elementary zones, c. determining, for each elementary zone of the image, a cost value as a function of at least one cost criterion, the at least one cost criterion relating to the overflight of the environment by the aircraft, d. sampling the main trajectory to obtain trajectory points, and e. for each diversion point, i. determining, as a function of the cost values determined for the elementary zones, cost distances between the diversion point and a set of elementary zones of the image in order to obtain a distance map, for each trajectory point included in the set of elementary zones, determining, as a function of the distance map, the minimum cost trajectory linking the said trajectory point to the diversion point, the trajectory determined being called the diversion trajectory, the method comprising an operating phase during which the aircraft flies over the environment initially following the main trajectory, the operating phase comprising: a. real-time determination of the position of the aircraft, and b. displaying, on a display, an image of the environment overflown by the aircraft, a representation of the following elements having been added to the image displayed: i. the main trajectory of the aircraft, ii. one or more diversion points, said added diversion point(s) being a function of the position of said diversion point(s) relative to the position of the aircraft determined in real time, and iii. the diversion trajectory determined between each diversion point represented on the image and the trajectory point closest in the direction of flight of the aircraft to the position of the aircraft determined in real time. a. obtaining an image of the environment intended to be overflown by the aircraft between a departure point and an arrival point, a representation of the following elements having been added to the image: i. a main trajectory intended to be travelled by the aircraft between the departure point and the arrival point, ii. at least one point of diversion of the aircraft away from the main trajectory, each point of diversion being a point in the environment away from the main trajectory and giving access to a safety zone, a safety zone being a zone away from a potential danger identified along the main trajectory, i. a main trajectory intended to be travelled by the aircraft between the departure point and the arrival point, ii. at least one point of diversion of the aircraft away from the main trajectory, each point of diversion being a point in the environment away from the main trajectory and giving access to a safety zone, a safety zone being a zone away from a potential danger identified along the main trajectory, b. meshing the image into elementary zones, c. determining, for each elementary zone of the image, a cost value as a function of at least one cost criterion, the at least one cost criterion relating to the overflight of the environment by the aircraft, d. sampling the main trajectory to obtain trajectory points, and e. for each diversion point, i. determining, as a function of the cost values determined for the elementary zones, cost distances between the diversion point and a set of elementary zones of the image in order to obtain a distance map, i. determining, as a function of the cost values determined for the elementary zones, cost distances between the diversion point and a set of elementary zones of the image in order to obtain a distance map, a. real-time determination of the position of the aircraft, and b. displaying, on a display, an image of the environment overflown by the aircraft, a representation of the following elements having been added to the image displayed: i. the main trajectory of the aircraft, ii. one or more diversion points, said added diversion point(s) being a function of the position of said diversion point(s) relative to the position of the aircraft determined in real time, and iii. the diversion trajectory determined between each diversion point represented on the image and the trajectory point closest in the direction of flight of the aircraft to the position of the aircraft determined in real time. i. the main trajectory of the aircraft, ii. one or more diversion points, said added diversion point(s) being a function of the position of said diversion point(s) relative to the position of the aircraft determined in real time, and iii. the diversion trajectory determined between each diversion point represented on the image and the trajectory point closest in the direction of flight of the aircraft to the position of the aircraft determined in real time.