Unmanned Aerial Vehicle (UAV) is becoming an important tool for military and civilian operations due to its growing applications. Examples of such applications are delivery, sensing, mapping, surveillance and search and rescue, where the manned mission is hard. The mathematical modelling of the UAV starts with the characterization of its kinematics, dynamics and forces and moments, which generates the 12 nonlinear ordinary differential equations. The aerodynamic flow in the design considers laminar flow in the operating velocity range. Linearization is performed around the equilibrium point, which is also called the trim condition. The trim condition depends on the flight scenario. Linearization generates the state space matrix, where the modelling is carried out with the decoupling of the longitudinal and lateral mode separately.