## 4 Results: Optimized Configurations
### Overall Performance Comparison at the Design Point
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**DOC [EUR/Flight]**} & \multicolumn{2}{c}{**CO\({}_{2_{curr}}\) [kg]**} & \multicolumn{2}{c}{**CO\({}_{2_{inter}}\) [kg]**} & \multicolumn{2}{c}{**CO\({}_{2_{err}}\) [kg]**} & \multicolumn{2}{c}{**m\({}_{fb}\) [kg]**} \\ \hline
**Tag** & **BW** & **TW** & **A\%** & **BW** & **TW** & **\(\Delta\)\%** & **BW** & **TW** & **\(\Delta\)\%** & **BW** & **TW** & **\(\Delta\)\%** & **BW** & **TW** & **\(\Delta\)\%** \\ \hline
23t & 6280 & 6592 & \(-5\) & 3112 & 3579 & \(-13\) & 2670 & 3223 & \(-17\) & 2228 & 2866 & \(-22\) & 705 & 907 & \(-22\) \\ \hline
30t & 7170 & 7590 & \(-6\) & 3282 & 3944 & \(-17\) & 2468 & 3226 & \(-24\) & 1654 & 2580 & \(-36\) & 523 & 816 & \(-36\) \\ \hline
40t & 8387 & 8802 & \(-5\) & 3643 & 4284 & \(-15\) & 2327 & 3139 & \(-26\) & 1011 & 1994 & \(-49\) & 320 & 631 & \(-49\) \\ \hline
50t & 9610 & 10,110 & \(-5\) & 4024 & 4854 & \(-17\) & 2238 & 325 generated. Still considering the current context, the situation is slightly better for BW, which in the '\(23t\)' and '\(30t\)' cases can achieve CO\({}_{2}\) reductions, albeit still quantitatively limited. The trend begins to reverse for the CO\({}_{2_{intr}}\) scenario, hence providing more relevant CO\({}_{2}\) reductions, while emission reductions coincide with fuel reductions in the CO\({}_{2_{intr}}\) case. These results highlight once again how the introduction of electric propulsion technologies alone is not sufficient on a global level if they are not coupled with the ecological transition of electricity production. As far as the economic impact is concerned, once again the BW has advantages over the TW, although this time much more limited compared to the other FoMs discussed; see Table 5. This is because the share of cost reductions related to electricity and fuel is weighted by a series of fixed costs that are common between the two configurations. Considering instead the DOC comparison with the thermal benchmark (see Table 7), it is observed that for any configuration as MTOW changes, there are economic disadvantages in operating hybrid-electric aircraft compared to the state of the art. According to the \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**CO\({}_{2_{intr}}\)**} & \multicolumn{2}{c}{**CO\({}_{2_{intr}}\)**} & \multicolumn{2}{c}{**CO\({}_{2_{intr}}\)**} & \multicolumn{2}{c}{**_m\({}_{fb}\)**} \\ \hline
**Tag** & **A\%BW** & **\(\Delta\)\%TW** & **A\%BW** & **\(\Delta\)\%TW** & **\(\Delta\)\%BW** & **\(\Delta\)\%TW** & **\(\Delta\)\%BW** & **\(\Delta\)\%TW** \\ \hline
23t & \(-14.3\) & \(-1.1\) & \(-26.4\) & \(-11.2\) & \(-38.6\) & \(-21.1\) & \(-38.6\) & \(-21.1\) \\ \hline
30t & \(-9.6\) & \(8.6\) & \(-32.0\) & \(-11.1\) & \(-54.4\) & \(-28.9\) & \(-54.4\) & \(-28.9\) \\ \hline
40t & \(0.4\) & \(18.0\) & \(-35.9\) & \(-13.5\) & \(-72.1\) & \(-45.1\) & \(-72.1\) & \(-45.1\) \\ \hline
50t & \(10.8\) & \(33.7\) & \(-38.3\) & \(-10.3\) & \(-90.2\) & \(-54.3\) & \(-90.2\) & \(-54.3\) \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Comparison of optimized hybrid-electric TW and BW and reference thermal TW considering CO\({}_{2}\) emission as FoM. Figure 10: Radar charts of the FoMs comparison between the optimal BW–TW configurations. MTOW: (**a**) \(23\times 10^{3}\) kg\({}_{t}\); (**b**) \(30\times 10^{3}\) kg\({}_{t}\); (**c**) \(40\times 10^{3}\) kg\({}_{t}\); (**d**) \(50\times 10^{3}\) kg\({}_{t}\). current estimates, the effect of the cost of electrical components and energy, which becomes more impactful as the MTOW increases, imposes a trade-off between the beneficial effects in terms of emissions and the increases in operating costs of hybrid-electric aircraft.