Accurate prediction of aerodynamic loads throughout multiple flight regimes is vital for the development of control algorithms for vehicles which pass through different regimes during the course of a flight. As such, a reducedorder modeling methodology based on linear convolution combined with a nonlinear correction factor initially developed for hypersonic flight has been extended to the transonic flight regime. Errors mostly remained small when the unsteady lift, drag and moment coefficient results were compared with direct CFD simulations over a range of oscillation frequencies and amplitudes, though the drag coefficient did show larger errors at higher oscillation frequencies. A methodology to determine the optimal number and location in the parameter space of the ROM construction sampling points has also been developed. Results showed good agreement between the coefficients calculated by this method and those calculated by direct CFD simulation.