The state-of-the-art in vehicle design decouples trajectory generation from shape optimization, which may result in an aeroshell design that does not meet in-flight requirements. The integration of a guidance algorithm into the design process can provide a real-time, rapid trajectory generation technique to improve vehicle design solutions. This work quantifies the performance of a reference tracking guidance algorithm, an Apollo Derived Guidance (ADG), for five different geometries using a single same reference trajectory. The guided trajectories are compared to the trajectories determined in a vehicle optimization study for a Mars Entry. The aerodynamic dispersions ranged from +/-1% to +/-17% and a single extreme case applies an aerodynamic dispersion of approximately 80% less than the baseline geometry. This study revealed that the generation of flight feasible trajectories is only as good as the robustness of the guidance algorithm. The ADG, as expected, was able to guide the vehicle into the separation box at the target location for dispersions up to 17%, but failed for the 80% dispersion case. Finally, the results revealed that including flight feasible trajectories for a set of dispersed geometries has the potential to save up to 430 kg of mass.