In this paper we will demonstrate the possibility of weight optimization of panels under aero-thermal loading in hypersonic flow using functionally graded materials (FGM). The in-plane volume fraction of two constituents (Aluminium and Nickel) is modelled using polynomial distributions. Different material grading layouts are investigated, including cases with Nickel concentrated at corners, sides, midpoints and center. The solution of the problem utilized a higher order element with C1 continuity. The study covers the linear boundaries of the panel flutter problem as well as the non-linear post-buckling deflections. The results indicated Nickel placement strategies are shown to enhance dynamic pressure and vibration performance for a given mass reduction through optimal center and edge localization. Overall, the integrated modelling approach demonstrates the potential to systematically optimize stability, weight and integrity in hypersonic flow to optimize the weight of panels subject to aero-thermal loads.