An aerodynamic airflow deflecting device for a landing gear retracting into a housing of an aircraft, comprising at least one element for closing the housing that is, through the action of a control device, able to occupy a position for shielding at least a part of the landing gear against the aerodynamic airflow, thus constituting a noise reducing aerodynamic device. The closing element can in particular include at least one trap door element that is, through the action of the control device, movable between a first position for closing the housing, a second position allowing the landing gear to exit and a third position constituting said shielding position.