Model-based design utilizing Simulink is state of the art in mechatronic system development. A key advantage is that developed control algorithms are deployed onto the target execution platform by automated code generation. For many robotic applications, the Robotic Operating System (ROS) is an attractive target execution platform with growing interest in UAV development such as aerial manipulation. The presented model-based design approach includes modular Guidance, Navigation and Control (GNC) development in Simulink and code generation of encapsulated ROS nodes for each of the GNC modules. To reduce control cycle latency, an automated code modification is proposed, for which design guidelines are given to define an efficient ROS node execution order. The modular approach is compared to a monolithic approach where just a single ROS node is generated for the complete GNC functionality. The design approach is demonstrated by flight experiments for an aerial screwing process where lateral contact forces at the manipulator tip are generated. Force estimation results compared to ground truth measurements show good agreement in flight experiment and simulation. For this case study, the modular design approach results in more than 73% time saving for code generation.