## 5 Conclusions  
This paper outlines the development of a consensus framework utilizing the blockchain for managing Unmanned Aircraft Systems (UASs) traffic. The smart contract was intended to assign secure airspace to the UASs. The consensus algorithm was formulated by drawing from both Proof of Work (PoW) and Proof of Stake (PoS) algorithms. The airspace was divided into multiple districts, where the smart contract's efficiency could be enhanced through reduced computational complexity. The findings demonstrated that sharding can lead to a decrease in both the error rate and validation time, underscoring the enhancement in consensus protocol performance with a higher number of shards. Considering conflict probabilities with various consensus protocols, the PoW offered a better safe airspace allocation than the PoS algorithm, in which the average probability of conflict for PoW was 8.7% less than PoS. In fact, the PoW outperformed PoS in terms of error rates. On the other hand, the cumulative execution probability with an increasing number of blocks using the PoS was definitely better than the PoW. Additionally, the PoS could provide a shorter validation time. Without paying attention to the utilized proof methodology, the leader-free approach showed lower error rates compared to those of the leader-based approach. Conceptualization, S.M.H. ; methodology, S.M.H. ; software, S.M.H. ; validation, S.M.H., R.M.B., and G.G. ; formal analysis, S.M.H. and G.G. ; investigation, S.M.H. ; resources, R.M.B. and G.G. ; data curation, S.M.H. and G.G. ; writing--original draft, S.M.H. ; writing--review and editing, R.M.B. and G.G. ; supervision, R.M.B. and G.G. ; project administration, R.M.B. ; funding acquisition, R.M.B. and G.G. All authors have read and agreed to the published version of the manuscript. This research was funded by Canada Research Chair in Aircraft Modeling and Simulation (NSERC) under the contract number: 231679, which made the realization of this research and the publication of this paper possible. [PERSON] is the Canada Research Chair Tier 1 Holder in Aircraft Modeling and Simulation New Technologies. Special thanks are due to the Natural Sciences and Engineering Research Council of Canada (NSERC) for the Canada Research Tier 1 in Aircraft Modeling and Simulation Technologies funds. We would also like to thank [PERSON] and [PERSON] for their support at ETS, as well as Hydra Technologies' team members [PERSON], [PERSON], and [PERSON] in Mexico. Finally, we wish to express our appreciation to the Canada Foundation for Innovation CFI, the Ministere de l'Economie et de l'Innovation, and Hydra Technologies for their support of the acquisition of the UAS-S4 at the LARCASE. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{4}{c}{**Error Rates \%**} \\ \hline
**Number of UASs** & \multicolumn{2}{c}{**Leader-Free**} & \multicolumn{2}{c}{**Leader-Based**} \\ \hline  & **PoW** & **PoS** & **PoW** & **PoS** \\ \cline{2-5}
10 & 0.21 & 0.43 & 0.32 & 0.67 \\
100 & 0.47 & 0.88 & 0.65 & 1.31 \\
1000 & 0.96 & 1.75 & 1.34 & 2.71 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Blockchain reliability analysis according to the control by various consensus mechanisms and with 3 scales of UAS numbers. **Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.