This paper presents an investigation of human comfort with a small Unmanned Aerial Vehicle (sUAV) through a study offering a comparison of comfort with a sUAV versus a ground vehicle. Current research on human comfort with sUAVs has been limited to a single previous study, which did not include free flight, and while ground vehicle distancing has been studied, it has never been directly compared to a sUAV. The novelty in the approach is the use of a motion capture room to achieve smooth trajectories and precise measurements, while conducting the first free flight study to compare human comfort after interaction with aerial versus ground vehicles (within subjects, N=16). These results will contribute to understanding of social, collaborative, and assistive robots, with implications for general human-robot interactions as they evolve to include aerial vehicles. Based on the reduced stress and distance (36.5cm or 1.2ft) for ground vehicles and increased stress and distance (65.5cm or 2.15ft) for sUAVs, it is recommended that studies be conducted to understand the implications of design features on comfort in interactions with sUAVs and how they differ from those with ground robots.