The invention provides an aircraft with a ventral fairing able to store equipment and systems in lateral zones. The ventral fairing (20) comprises a first zone of length L1 along the X-axis, where the area of the cross-section perpendicular to the X-axis increases in the direction of the air flow and a second zone of length L2, where the area of the cross-section perpendicular to the X-axis decreases in the direction of the air flow, being L1>L2 and being placed the rear end of said first zone behind the intersection of the trailing edge of the wing (15) with the fuselage (13).