Projected region-of-attraction analysis of coupled two-region low-altitude air traffic using microsimulation-calibrated MFDs

Low-altitude air traffic (LAAT) management requires macroscopic models that represent interactions between regional demand and service allocation. This study develops a projected stability-analysis framework for a two-region macroscopic fundamental diagram (MFD) model with intra- and inter-regional aircraft accumulations. Regional MFDs are independently calibrated from trajectory-level agent-based microsimulation; held-out \:R² values are 0.675 and 0.892. Bootstrap resampling propagates calibration uncertainty to projected region-of-attraction (RA) boundaries and areas. A variance-based Sobol analysis jointly evaluates capacity-normalized demand loading, prescribed background accumulation, and service allocation. Destination-region demand loading has the largest total-order effect in both directional projections, followed by inter-regional transfer-demand loading; their pairwise interaction is also the strongest. Service-allocation effects are smaller but non-negligible, whereas the prescribed accumulation ranges contribute little to RA-area variance. The results support comparative stability assessment, although the estimated boundaries remain scenario-specific rather than field-validated operational thresholds.