On Saturday morning, the departure boards at King Khalid International Airport in Riyadh would normally have shown flights bound for Dubai, Cairo and London. Instead, the terminal stood largely empty, its runways scarred by an attack that killed at least 12 people and wounded more than 300. The strike, which Saudi officials have attributed to Yemen's Houthi rebels, marks one of the deadliest assaults on Saudi civilian infrastructure in years and has reignited a conflict that many in the region had hoped was cooling. The attack drew an unusually blunt response from US President Donald Trump, who called it "not acceptable" and signalled that Washington would stand behind its longtime Gulf partner.

Saudi Arabia, for its part, has promised retaliation against the Houthis, raising the prospect of a renewed cycle of strikes between Riyadh and the Iran-aligned group that controls much of northern Yemen. The Houthis have not formally claimed responsibility, though Saudi officials say evidence points clearly to the group, which has previously targeted Saudi oil facilities and shipping lanes in the Red Sea. The timing is significant. Riyadh has spent the past two years cultivating an image of stability, courting foreign investment for Crown Prince Mohammed bin Salman's economic diversification plans while quietly pursuing backchannel talks with Houthi representatives.

An attack on the kingdom's busiest airport undercuts both efforts at once, reminding investors from Tokyo to New York that the war in Yemen, though less visible in recent headlines, remains unresolved. For ordinary Saudis and the thousands of foreign workers who pass through Riyadh's airport daily, the strike has introduced a fear that had receded since the fiercest years of the Yemen war.