Heathrow Airport has warned it expects passenger numbers for the rest of the year to be affected by the Iran war.
Some 18.9 million people passed through its four terminals during the first three months of the year, a year-on-year increase of 3.7%, which the west London airport said was because it "temporarily absorbed demand from elsewhere".
In a trading update, the airport said: "Passenger numbers for the rest of the year are likely to be impacted whilst there is significant uncertainty in the Middle East."
Airspace closures in the area following the outbreak of the war on 28 February has had a major impact on air travel.
About half a million passengers per day usually use airports in Dubai, Doha or Abu Dhabi, which are used as connecting hubs between Europe, Asia and Australia.
