Modern aircrafts are becoming lighter and more flexible to meet fuel efficiency, endurance and other requirements. The structural modes therefore occur at lower frequencies and there is an increased coupling between the structural and rigid body modes. A general approach is to design control laws for the rigid body modes and then apply filters which avoid the excitation of the structural modes. However this approach is not possible in lighter and more flexible aircrafts, due to the coupling of the structural and rigid body modes. In this report several control methods are developed to prevent a flexible wing aircraft from fluttering. State space models with a flight envelope ranging from 40 Knots Equivalent Air Speed (KEAS) to 90 KEAS are used. The models consist of 182 states, 8 inputs and 13 outputs. The models are reduced using various model reduction steps like truncation, (modal) residualization and balanced truncation. After this model reduction different control techniques, namely Linear Quadratic Gaussian (LQG) control, Linear Parameter Varying control and L1Adaptive control, are investigated using different examples and applied on the flexible wing aircraft.