## 3 Conceptual Model Development
### Service-Oriented On-Demand Air Mobility Model  
As the model would also be used for ODAM scenarios, any customer could initiate the process by requesting a flight. To satisfy these requests, four different elements and processes were coordinated to ensure customer satisfaction. These elements and processes are shown in Figure 7. First, the availability of the electric aircraft, i.e., that the aircraft was on-site with enough energy and without maintenance needs; secondly, the availability of the pilot and crew on-site; third, the correct and timely order processing, and, finally, that the customer was in the vertiport at the right time. All these elements and processes were tracked and optimized for successful ODAM operations:  
As shown in Figure 8, the service model for ODAM depended on four resources within a given mobility network. Therefore, by adding a given or potential new mobility  
Figure 6: Electric Aviation Mobility Elements.  
Figure 7: On-Demand Air Mobility Requests.  
network, there were five elements by which to assess and improve the performance of the service model.  
For each of the service model elements, there were factors influencing the overall customer service provision. For the aircraft, these were its availability and performance. The pilot and the crew involved their availability and qualifications. The customer satisfaction depended on the effectiveness and efficiency of their order processing from the initial request to their arrival at their destination. For the mobility network, these were the quantity of the different spaces within the mobility network, i.e., how to manage the capacities of vertiports and places as well as how many spare parts and means were to be allocated for proper operations and maintenance of the aircraft units. Finally, for the service model, the customer had to be on-site and on-time, so an effective and efficient customer request and order processing was fundamental. The customer request and order processing for ODAM systems would also likely involve how a customer request could be placed and what communications platforms could be used (e.g., via internet with smartphones, laptops, or other devices).  
As these requests for pairs of origins and destinations had not been associated with an aircraft, these requests were \"process-to-stock\", as they were stored until an aircraft was assigned. When an aircraft was associated and a flight was planned, then the requests were converted into orders, and they were considered \"process-to-order\". In the process of assigning an electric aircraft for a given request, one may not be available. Moreover, upon aircraft arrival and preparation to land, parking bays may not be available in the landing vertiport. As a result, for improving service levels, the global customer order lead time needed to be minimized. For doing so, three elements were key, as shown in Figure 9. If the push-pull boundary moved closer to the customer, the real mobility demand would need to be known earlier, and the request processing lead time would be lower, making the time span for planning purposes higher. The second key element was assuring the availability of charged electric aircraft units without further maintenance needs in each vertiports as this would reduce the assignment waiting times of aircraft. The third element referred to the waiting times for landing and parking at the destination. Therefore, ensuring landing space was essential in reducing flight-related lead times.  
Figure 8: Service model and its five elements.  
Figure 9: Customer Request Processing: Push-pull boundary and non-availability of aircraft and parking places.