This chapter starts with modelling flutterFlutter analysis, which is usually represented by a critical speed leading to instability similar to the cases of divergenceDivergence speed. Then, several flutterFlutter solution techniques based on sweeping reduced frequencyReduced frequency and velocity are presented. Gust responseGust response is the subsequent section, consisting of discrete and continuous gustsContinuous gust. The final part deals with the aeroelastic modelling of a full aircraft with several modelling conditions, including gust and control inputs.