A device (10) for defining a flight path (2) enabling an aircraft (1) to reach a destination (B), said device (10) including a digital terrain model (21) and a display screen (30), and being provided with generator means (15) for generating a flight path (2) including at least one flight segment (3) associated with a flying altitude. The device (10) includes a digital noise database (20) having volumes that are to be avoided, said device (10) having a computer (11) with a main memory (13) containing instructions for displaying on said display screen (30) and as an overlay on a first representation (31) of said terrain as provided by said digital terrain model (21): a second representation (41) of said volumes to be avoided; and a flight path (2) that has been generated by using said generator means (15).