Internet of things (IoT) is currently adopted in every possible area such as industrial, healthcare, traffic-monitoring, and military applications. The deployment of IoT in the military area has a huge concern of security. Unmanned aerial vehicle (UAV) is being used in military applications since it is first invented and with the rapid growth of IoT devices the use of UAV has become more essential. Blockchain is a peer-to-peer network which in recent has been occupied by every field for the security purpose. In this paper, we analyzes the security challenges towards the deployment of UAV and IoT devices to create wireless communication in military networks. To provide the security and reliability we adopted the blockchain technology. The significant impact of using blockchain technology on the deployment of UAV and IoT devices is discussed thoroughly. Finally, future research direction and open issues are discussed in conclusion.