The use of drone systems is increasing especially in dangerous environments where manned operations are too risky. Different entities are involved in drone systems' missions and they come along with their vast varieties of specifications. The behaviour of the system is described by its set of policies that should satisfy the requirements and specifications of the different entities and the system itself. Deciding the policies that describe the actions to be taken is not trivial, as the different requirements and specifications can lead to conflicting actions. We introduce an argumentation-based policy analysis that captures conflicts for which properties have been specified. Our solution allows different rules to take priority in different contexts. We propose a decision making process that solves the detected conflicts by using a dynamic conflict resolution based on the priorities between rules. We apply our solution to two case studies where drone systems are used for military and disaster rescue operations.