How do you implement a multi-fidelity aerodynamic analysis approach for aircraft design?

Multi-fidelity analysis balances accuracy and computational cost through design phases: Conceptual design uses handbook methods (DATCOM), vortex lattice, panel methods; Preliminary design employs Euler CFD, panel-boundary layer coupling; Detailed design uses RANS CFD with validation against high-fidelity benchmarks and wind tunnel data; Final certification involves comprehensive RANS/hybrid RANS-LES with uncertainty quantification. Kriging or co-kriging surrogate models fuse multi-fidelity data for optimization. Calibration factors correct lower fidelity results. Key is understanding each method's limitations: VLM misses viscous effects, Euler misses separation, RANS may mispredict complex separated flows requiring DES/LES.