Lisbon Humberto Delgado Airport — Lisbon, Portugal

Wedged within Lisbon's city limits, close enough that the descent path takes arriving flights directly over the capital's rooftops, LIS has functioned for decades as both a convenience and a constraint, offering a short ride into the historic center while limiting room to expand. The airport bears the name of Humberto Delgado, a former air force general and popular opposition candidate who challenged the Estado Novo dictatorship in a fraudulent 1958 presidential election and was later assassinated by the regime's secret police in 1965. As the primary hub for TAP Air Portugal, LIS anchors an extensive network linking Portugal to its former colonies in Brazil and Africa, a legacy of colonial-era air routes that still shapes the carrier's long-haul strategy today. Decades of debate over a replacement airport, including a proposed site at Montijo, stalled repeatedly over cost and environmental concerns, leaving Lisbon's original airport still the country's busiest.