The increasing use of fibre-reinforced plastics in the aerospace industry leads to challenges in joining these materials. The traditionally used mechanical fasteners introduce damage when used in composites by disrupting the fibres. However, thermoplastic composites allow for fusion bonding processes to join parts. Ultrasonic welding has shown to be a very promising high-speed fusion-bonding technique for thermoplastic composites. At the moment, a thorough understanding of the process is required to upscale the process for industrial usage. This study focuses on defining a roadmap to develop continuous ultrasonic welding to an industrially applicable level by presenting the current state of the art, ongoing developments, requirements, and challenges.@en