View Video Presentation: https://doi.org/10.2514/6.2023-3554.vid The number of uncrewed aircraft systems (UAS) and corresponding UAS operations is expected to increase dramatically soon. Regulatory agencies are currently designing and piloting UAS traffic management concepts that rely on federated protocols and a cooperative, community-based approach. As demand increases, the need to ensure fair usage of airspace among operators will be an important challenge. Currently, there are no widely agreed upon definitions or guidelines for UAS airspace fairness. The objective of this work was to evaluate the fairness implications of using a first-filed-first-served protocol for flight planning. We developed UAS Cooperative Airspace Traffic Simulation (UCATS), an agent-based modeling simulation tool, to evaluate different UAS package delivery scenarios using a first-filed-first-served approach to UAS flight planning. We defined key metrics to measure fairness, including average delay, maximum delay, and percentages of flights as planned, replanned, and canceled. Our results showed that a first-filed-first-served approach may cause flights having a departure time later in the day and flights that are filed with less advanced time have a higher probability of experiencing more negative flight outcomes. We also evaluated the sensitivity of fairness metrics to different traffic levels, different flight densities, and the addition of food delivery operations.