The general field of the invention is that of methods for determining safety zones surrounding an aircraft travelling or taking off from an airport zone, the safety zone being calculated at a determined instant that may be the present instant or the future instant. The method according to the invention comprises at least the following steps: Step 0: Establishment of a convex safety envelope surrounding the aircraft on the basis of reference points taken on the aircraft; Step 1: Establishment of a first convex envelope safety zone surrounding the aircraft on the basis of reference circles taken on the aircraft, each circle having as center one of the reference points and as radius the value of the uncertainty in the exact position of the aircraft. Other steps of the method make it possible to refine this first safety zone depending on whether the aircraft is in a taxiing or takeoff phase and depending on whether it is calculated at the present instant or at the future instant.