We describe how establishing goals at different levels of abstraction helps a human operator to supervise/control a system consisting of multiple unmanned air vehicles. In particular we focus on the importance of including Human Machine Interaction within the design of an autonomous system. Important lessons include being explicit about the level of authority to delegate to the automated part of the system and viewing the interaction between the human and the automated planning/execution system as a partnership, thus facilitating a shared awareness of, and commitment to, joint goals.