An air intake unit for an engine of an aircraft; the intake unit comprises: a tubular housing, which has a longitudinal symmetry axis, is provided with an outer wall delimiting the space enclosed by the tubular housing, and has a front portion and a rear portion; at least one first inlet opening which is obtained in the rear portion through the outer wall of the tubular housing and through which the external air needed to operate the engine can be taken in; at least one air filter which is supported by the tubular housing and engages the first inlet opening, so as to filter the external air flowing through the first inlet opening; at least one second inlet opening which is obtained in the front portion through the outer wall of the tubular housing, is separate from and independent of the first inlet opening and the air filter, and through which the external air needed to operate the engine can be taken in; a shutter device which is coupled to the second inlet opening and is movable between a closed position, in which it closes the second inlet opening, and an open position, in which it sets the passage through the second inlet opening free; and an actuator, which moves the shutter device between the closed position and the open position; wherein the filtering material of the air filter is arranged in the area of a side wall of the air filter, allows an air crossing both in axial direction and in radial direction with respect to the longitudinal symmetry axis, and has, on its front and rear side, respective free openings; the intake unit is characterized in that: the rear portion provided with the first inlet opening has the shape of a truncated cone; the air filter engaging the first inlet opening has the shape of a truncated cone; and the front portion provided with the second inlet opening is ogive-shaped. a tubular housing, which has a longitudinal symmetry axis, is provided with an outer wall delimiting the space enclosed by the tubular housing, and has a front portion and a rear portion; at least one first inlet opening which is obtained in the rear portion through the outer wall of the tubular housing and through which the external air needed to operate the engine can be taken in; at least one air filter which is supported by the tubular housing and engages the first inlet opening, so as to filter the external air flowing through the first inlet opening; at least one second inlet opening which is obtained in the front portion through the outer wall of the tubular housing, is separate from and independent of the first inlet opening and the air filter, and through which the external air needed to operate the engine can be taken in; a shutter device which is coupled to the second inlet opening and is movable between a closed position, in which it closes the second inlet opening, and an open position, in which it sets the passage through the second inlet opening free; and an actuator, which moves the shutter device between the closed position and the open position; wherein the filtering material of the air filter is arranged in the area of a side wall of the air filter, allows an air crossing both in axial direction and in radial direction with respect to the longitudinal symmetry axis, and has, on its front and rear side, respective free openings; the intake unit is characterized in that: the rear portion provided with the first inlet opening has the shape of a truncated cone; the air filter engaging the first inlet opening has the shape of a truncated cone; and the front portion provided with the second inlet opening is ogive-shaped. the rear portion provided with the first inlet opening has the shape of a truncated cone; the air filter engaging the first inlet opening has the shape of a truncated cone; and the front portion provided with the second inlet opening is ogive-shaped.