An aircraft having a sponson extending substantially transversely relative to a main body of the fuselage of the aircraft and substantially perpendicularly relative to a vertical anteroposterior plane of symmetry P of the main body of the fuselage when the aircraft is standing on a horizontal support, the sponson including a notch locally reducing a cross-section of the sponson in a connection zone of the sponson, the connection zone being suitable for being arranged in the immediate proximity of the main body of the fuselage of the aircraft from which the sponson emerges transversely, the notch being open at least to a front outside face and to a top outside face of the sponson and being suitable for receiving a bottom portion of a sliding side door when in its open position.