The DLR-project STORMIE investigates novel concepts for supersonic passenger transport, with a particular focus on low boom characteristics. Three aircraft designs are being developed and analyzed for this purpose. This paper presents a flight mechanics analysis of one of these aircraft designs - a supersonic business jet - conducted during the early stages of aircraft design within the DLR project STORMIE. Key characteristics of the investigated aircraft design are briefly presented, along with the workflow used to generate the configuration dataset, which is a prerequisite for the flight mechanics analysis. A six-degrees-of-freedom flight dynamics model, based on aerodynamic, propulsion, and mass properties data, is applied for the flight mechanics analysis. Furthermore, the software environment used for the flight performance analysis and the investigated flight conditions are described. A brief theoretical background on the flight mechanics requirements is outlined, and the results of the conducted analyses are presented and discussed. The flight mechanics analysis has shown that not all flight performance parameters yet meet the specified requirements. Furthermore, the aircraft’s stability presents challenges in certain regions of the flight envelope, necessitating a review of the aircraft design.