Iran, Iraq and Jordan closed their airspace and Israel shut its main airport on Friday after Israeli strikes disrupted global aviation.
Thousands of flights were cancelled or diverted, with Eurocontrol estimating at least 1,800 affected in Europe alone.
Airlines including El Al, Air France, Lufthansa, Ryanair, and Qatar Airways suspended or rerouted operations.
Shares in major carriers fell, and oil prices surged amid fears of escalation.
