The integration of Unmanned Aircraft Systems (UAS) into the National Air Space (NAS) in recent times has been met by mixed public responses. The paper establishes four constructs each of which encapsulates multiple backgrounds and concerns of the stakeholders: functional knowledge, utilization trust, operational integration support, and safety risk-benefits. The paper hypothesizes that these constructs can serve as underlying components for a research instrument namely, the Public Utilization Perception Potential (PUPP) which can be used to assess the opinions of the public on UAS integration into NAS. Responses from the public on items in a beta-tested survey instrument were analyzed for construct validity and reliability using Principal Axis Factoring (PAF). Four factors that suggest constructs underlying PUPP instrument were derived. Using Structural Equation Model (SEM) approach, a hypothesized measurement model of PUPP was further validated and the final measurement model showed good fit of the observed data based on the RMSEA goodness-of-fit index (0.034). The paper further assessed the strength of relationships between the underlying constructs of PUPP. The results suggest that approximately 65% and 27% of all respondents had partial and no knowledge, respectively, about UAS integration into the NAS. There was a statistically significant difference in the mean scores on safety-risk benefits on UAS among gender. Males were found to be more likely to patronize unmanned commercial passenger services compared to females. The results indicated a statistically significant difference in UAS knowledge and perceptions across educational levels. It was rather counter-intuitive as respondents with lower educational levels were found to be more knowledgeable about UAS compared to those of higher levels based on the results of this study. Investments in information resources and training by industry, government and academia may be helpful to improve UAS knowledge and perceptions among the public if any commercial utilization as a transport mode will be feasible. Future studies will replicate the study in countries other than the United States.