A piezoelectric actuated droplet delivery device for generating and delivering a fluid as an ejected stream of droplets to a pulmonary system of a subject, the piezoelectric actuated droplet delivery device comprising: an ejector mechanism comprising a piezoelectric actuator and an aperture plate, the aperture plate having a plurality of openings formed through its thickness and the piezoelectric actuator operable to oscillate the aperture plate at a frequency to thereby generate the ejected stream of droplets; the droplet delivery device characterized in that: the droplet delivery device comprises a housing having a mouthpiece located at an airflow exit of the housing, and an airflow laminar flow element located opposite the mouthpiece and at an airflow entrance of the housing; wherein the airflow laminar flow element is configured to facilitate laminar airflow across an exit side of the aperture plate; and the laminar flow element includes a number of holes wherein the size, number, shape and orientation of the holes are configured to generate an internal airflow resistance within the device and to provide sufficient airflow through the device housing during use; the droplet delivery device is configured to: (a) generate said ejected stream of droplets, wherein at least 70% of the ejected stream of droplets have an average ejected droplet diameter of less than about 5 μm. an ejector mechanism comprising a piezoelectric actuator and an aperture plate, the aperture plate having a plurality of openings formed through its thickness and the piezoelectric actuator operable to oscillate the aperture plate at a frequency to thereby generate the ejected stream of droplets; the droplet delivery device characterized in that: the droplet delivery device comprises a housing having a mouthpiece located at an airflow exit of the housing, and an airflow laminar flow element located opposite the mouthpiece and at an airflow entrance of the housing; wherein the airflow laminar flow element is configured to facilitate laminar airflow across an exit side of the aperture plate; and the laminar flow element includes a number of holes wherein the size, number, shape and orientation of the holes are configured to generate an internal airflow resistance within the device and to provide sufficient airflow through the device housing during use; the droplet delivery device is configured to: (a) generate said ejected stream of droplets, wherein at least 70% of the ejected stream of droplets have an average ejected droplet diameter of less than about 5 μm. the droplet delivery device comprises a housing having a mouthpiece located at an airflow exit of the housing, and an airflow laminar flow element located opposite the mouthpiece and at an airflow entrance of the housing; wherein the airflow laminar flow element is configured to facilitate laminar airflow across an exit side of the aperture plate; and the laminar flow element includes a number of holes wherein the size, number, shape and orientation of the holes are configured to generate an internal airflow resistance within the device and to provide sufficient airflow through the device housing during use; the droplet delivery device is configured to: (a) generate said ejected stream of droplets, wherein at least 70% of the ejected stream of droplets have an average ejected droplet diameter of less than about 5 μm. (a) generate said ejected stream of droplets, wherein at least 70% of the ejected stream of droplets have an average ejected droplet diameter of less than about 5 μm.