Little is understood about national defence and its unique conflicts in spatial planning. Additionally, a growing body of literature describes agonism applied to planning conflicts. By studying the military training lands in Jægerpris and the conflict surrounding it, this article sheds light on the Danish National Defence’s role and authority in spatial planning. This simultaneously contributes to a better understanding of agonism and irreconcilable planning conflict. This is done using Pieter Stallen’s work to describe noise conflicts as social events, Chantal Mouffe’s concept of agonism applied as fair procedure and Torben Dyrberg’s power concept to deconstruct the social aspect of noise management procedures. The conflict history is studied through newspaper articles and interviews with the main actors. The main arguments are that the noise management is perceived widely different by the National Defence, Frederikssund Municipality and the neighbours of the training lands. These perceptions surfaces as antagonism in the procedures of the noise management. The hegemony of the National Defence exiles the other discourses from the noise management, which further entrenches the conflict. Despite this hegemony, the National Defence voluntarily made accommodations, suggesting potential for agonistic discussion to facilitate better cooperation.