In an effort to reduce costs and time to deploy mission capable unmanned aerial vehicles (UAV), the Department of Defense (DoD) has transitioned smart devices into the battlefield as portable, handheld UAV ground control stations (GCS) without adequate cybersecurity protection. While a number of threat model approaches have been published, they are outdated and fail to evaluate a complete system. This article develops a holistic threat model that analyzes the cybersecurity vulnerabilities within the communication network, smart device hardware, software applications, as well as the insider threat. Additionally, this article provides a risk-based threat profile of a DoD pilot UAV smart device GCS system. This model will fill the gaps in current threat model approaches, to provide the DoD with a tool to properly assess the threat environment of a UAV smart device GCS, and build layers of security into the system throughout the system development life cycle.