In this work we present a systematic approach to incorporating the dynamic capabilities of an aircraft via suitable cost functions while planning for terrain following-terrain avoidance trajectories. We further show that use of nondimensional parameters related to the dynamics of an aircraft within the cost function provides a better understanding of how they could affect the resulting trajectories. Different case studies for arbitrary three-dimensional flights show that the current approach provides more realistic trajectories and so helps alleviate the design process of relevant controllers as well as tracking systems over the desired terrain. We further introduce two new parameters of "required in terrain maneuvering capability" and "available in terrain maneuvering capability," which evaluate an aircraft for terrain-following missions in the early stages of its design process. They can also help categorize existing aircraft for such capabilities.