Embodiments described herein are methods and systems that relate to delivery of a payload to a particular delivery surface. A payload is collected at a first physical location using a retractable delivery mechanism of a UAV, and the UAV flies to a designated second physical location, whereupon sensor data is obtained using one or more sensors of the UAV. The sensor data is used to obtain characteristics of an area which may be used as a delivery surface at the second physical location. An actual delivery surface is selected based on criteria in the form of rule data specifying an appropriate delivery surface and the sensor data. Once the delivery surface has been selected the retractable delivery lowers the payload towards the selected delivery surface.