## 5 Conclusions  
In VDTNs, the selfishness of communication nodes leads to relay nodes refusing to receive message copies from non-cooperative nodes, thereby reducing network performance. Although traditional incentive schemes promote cooperation among nodes, they result in high-resource consumption by non-selfish nodes with high centrality, which also decreases network performance. Motivated by the above, we investigated the opportunistic transmission problem in integrated UAV-ICV networks. By using the \"store-carry-forward\" transmission mechanism, an opportunistic transmission scheme for integrated UAV-ICV networks, enabled by node cooperation, was proposed. According to the selfish behavior of nodes in the actual use scenario, the cooperation type and encounter probability of nodes were modeled and analyzed. Then, by jointly considering the node centrality, energy consumption, and cache size, information was initially flooded and transmitted with the assistance of UAVs. Finally, this paper performed simulations using real maps to evaluate the performance of the proposed opportunistic transmission scheme. It was observed that compared to state-of-the-art schemes, the delivery ratio was improved, and the average delivery delay was reduced. Additionally, the influence of network parameters (e.g., the proportion of selfish nodes, cooperation thresholds, and number of nodes) on the delivery ratio and average delivery delay was fully demonstrated. In addition to the issues outlined in the previous sections, numerous research issues warrant further exploration. First, this paper assumed that the communication range and rate for integrated UAV-ICV networks are fixed. However, in actual vehicular networks, the communication range and rate dynamically change with environmental factors such as building density, power, and spectrum. In future work, it is necessary to combine our previous work [14] to further optimize the transmission mechanism and improve network performance. Additionally, this paper sets the mobility model for both UAVs and ICVs based on the SPMBM model using the Dijkstra algorithm. However, the movement of UAVs should theoretically be constrained by regulations. Meanwhile, the mobility of ICVs is influenced by social attributes, and the mobility model should not be singular. Thus, we  
Figure 9: The impact of the number of nodes on the average delivery delay. can further explore the impact of mobility models on the delivery ratio and average delivery delay. Nevertheless, the opportunistic transmission scheme proposed in this paper offers important insights and points out a promising direction for the design of relay selection protocols in the presence of selfish nodes within integrated UAV-ICV networks. M.Y. : conceptualization, methodology, software, writing--original draft preparation, and visualization. Z.Z. : conceptualization, methodology, software, and writing--original draft preparation. L.Z. : data curation, resources, and funding acquisition. F.H. : conceptualization, methodology, and formal analysis. T.L. : formal analysis, resources, and writing--review and editing. D.W.: conceptualization, resources, and writing--review and editing. Y.J. : software, resources, and writing-review and editing. Y.H. : conceptualization, resources, writing--review and editing, supervision, project administration, and funding acquisition. All authors have read and agreed to the published version of this manuscript. This work was supported in part by the \"Pioneer\" and \"Leading Goose\" R&D Program of Zhejiang under Grants 2024C04004 and 2023C01162, in part by the National Natural Science Foundation of China under Grants 62401230, 62271399, and 62201462, in part by the National Key Research and Development Program of China under Grant 2024 YFC2206804, in part by the General Research Projects of Zhejiang Provincial Department of Education under Grant Y202352050, and in part by the Student Research Training Program of Jiaxing University. Not applicable.