Portugal’s airports faced widespread disruption after a border‑control systems failure in Lisbon triggered long delays that quickly rippled across the country, slowing passenger processing and straining operations in Porto as well. With automated checkpoints offline, manual inspections created bottlenecks at arrivals and departures, leading to crowded terminals, extended queues, and slower aircraft turnaround. Airlines adjusted schedules while ground crews worked under pressure to maintain operations amid winter weather and heavy holiday traffic. The situation underscored how a single point of failure in national infrastructure can cascade through the entire aviation network on one of the year’s busiest travel days.