  With the rapid advance of sophisticated control algorithms, the capabilities
of drones to stabilise, fly and manoeuvre autonomously have dramatically
improved, enabling us to pay greater attention to entire missions and the
interaction of a drone with humans and with its environment during the course
of such a mission. In this paper, we present an indoor office drone assistant
that is tasked to run errands and carry out simple tasks at our laboratory,
while given instructions from and interacting with humans in the space. To
accomplish its mission, the system has to be able to understand verbal
instructions from humans, and perform subject to constraints from control and
hardware limitations, uncertain localisation information, unpredictable and
uncertain obstacles and environmental factors. We combine and evaluate the
dialogue, navigation, flight control, depth perception and collision avoidance
components. We discuss performance and limitations of our assistant at the
component as well as the mission level. A 78% mission success rate was obtained
over the course of 27 missions.
