Runway–Corridor Composition Shapes Capacity Responses to Multi-Airport Demand Reallocation

Traffic reallocation is usually framed as moving flights toward apparent spare airport capacity, yet the same move can redirect demand through different runways and shared corridors. We tested whether the local capacity response to a fixed reallocation remains invariant to this resource-chain composition. Using a discrete-event model of the Beijing Capital, Beijing Daxing and Tianjin Binhai airports, we crossed seven airport allocations with five prespecified composition levels. At a model-success threshold of 0.90, increasing Beijing Capital’s share by five percentage points produced a finite-search response of [−145,−115] flights under the lower-pressure composition but [10,25] under the higher-pressure composition. The propagated interaction interval was [125,170] flights. The reversal was consistent across three independent seed families, and 95% paired-bootstrap percentile intervals excluded zero for both outer compositions. None of 100 prespecified pressure-label controls met the certain-tail criterion, while seven control intervals overlapped the observed band. These are reference-tail proportions, not a randomization p-value. Runway and corridor relief each restored all seven failing operating-state boundary cases. These results show that reallocation acts on a coupled airport–resource system whose response depends on the complete chains carried by demand. These findings are model-conditional finite-search results under expert-bounded perturbations, not an official capacity determination or a calibrated estimate of operational reliability.