An electronically actuated droplet delivery device for delivering a fluid as an ejected stream of droplets to the pulmonary system of a subject, the device comprising: a housing; a mouthpiece positioned at an airflow exit of the device; an air inlet flow element positioned in the airflow at an airflow entrance of the device; an electronically actuated ejector mechanism in fluid communication with the reservoir and configured to generate the ejected stream of droplets; at least one differential pressure sensor positioned within the housing, the at least one differential pressure sensor configured to activate the ejector mechanism upon sensing a pre-determined pressure change within the mouthpiece to thereby generate the ejected stream of droplets; the 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; wherein the housing, air inlet flow element, and mouthpiece are configured to facilitate non-turbulent airflow across an exit side of the aperture plate and to provide sufficient airflow through the housing during use; and wherein the ejector mechanism is configured to generate the ejected stream of droplets wherein at least about 50% of the droplets have an average ejected droplet diameter of less than about 6 microns, such that at least about 50% of the mass of the ejected stream of droplets is delivered in a respirable range to the pulmonary system of the subject during use wherein the device further comprises: a small volume drug ampoule (900, 1003) comprising a drug reservoir coupled to the ejector mechanism to form a combination reservoir/ejector mechanism module, the combination reservoir / ejector mechanism module being removably coupled with the housing so as to be disposed in or in fluid communication with the housing, characterized in that the drug reservoir is sized to receive a small volume of fluid and includes an internal flexible membrane separating the internal volume in to a first background pressure fluid volume and a second drug volume. a housing; a mouthpiece positioned at an airflow exit of the device; an air inlet flow element positioned in the airflow at an airflow entrance of the device; an electronically actuated ejector mechanism in fluid communication with the reservoir and configured to generate the ejected stream of droplets; at least one differential pressure sensor positioned within the housing, the at least one differential pressure sensor configured to activate the ejector mechanism upon sensing a pre-determined pressure change within the mouthpiece to thereby generate the ejected stream of droplets; the 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; wherein the housing, air inlet flow element, and mouthpiece are configured to facilitate non-turbulent airflow across an exit side of the aperture plate and to provide sufficient airflow through the housing during use; and wherein the ejector mechanism is configured to generate the ejected stream of droplets wherein at least about 50% of the droplets have an average ejected droplet diameter of less than about 6 microns, such that at least about 50% of the mass of the ejected stream of droplets is delivered in a respirable range to the pulmonary system of the subject during use wherein the device further comprises: a small volume drug ampoule (900, 1003) comprising a drug reservoir coupled to the ejector mechanism to form a combination reservoir/ejector mechanism module, the combination reservoir / ejector mechanism module being removably coupled with the housing so as to be disposed in or in fluid communication with the housing, characterized in that the drug reservoir is sized to receive a small volume of fluid and includes an internal flexible membrane separating the internal volume in to a first background pressure fluid volume and a second drug volume.