A method for guidance and for assisting in following a trajectory for velocity-vector piloting of an aircraft includes a step of calculating, at all times, lateral and vertical offsets of the current position of the aircraft from a target trajectory, estimated by a flight management system, and then a joining heading and a joining gradient for the aircraft to join the trajectory depending on these offsets; and a following fourth step of displaying, in head-up or head-down form, a consistent guidance symbol centered on the calculated joining heading and the calculated joining gradient for joining the trajectory, on a piloting screen showing a velocity vector. The fourth step may display, in addition to the guidance symbol, one or more items of information anticipating the next trajectory break.