devices , systems , and methods for measuring the diameter of an airway in a human or animal subject are disclosed . the device comprises a flexible catheter body having a proximal end and a distal end . flexible sizing elements are disposed along and extend approximately orthogonally from the catheter body . the sizing elements have different heights from one another and are configured to fit through the working channel of a bronchoscope . devices , systems , and methods for redirecting airflow through a lung airway are also disclosed . the method comprises introducing into the airway a catheter comprising a distal end , a proximal end and an elongated portion therebetween , wherein the distal end comprises an airway closing mechanism , and wherein the proximal end comprises an actuator to actuate the airway closing mechanism ; and actuating the airway closing mechanism to at least partially close the airway .