Heathrow is the UK’s largest airport, with more than 83.9 million passengers travelling through its terminals in 2024. Here are some key figures about the airport and the impact of its closure following a fire at an electrical substation. – 229,000 passengers travel through Heathrow on an average day. – 1,357 flights have been disrupted on Friday, including 679 arrivals and 678 departures. – 120 flights were already in the air when the closure was announced. – More than nine in 10 passengers using Heathrow are travelling to or from other countries. Of the 83.9 million passengers recorded at the airport in 2024, 78.8 million were using international services – 28.1 million for services with other EU countries and 50.7 million for non-EU countries. Domestic passenger traffic accounted for 5.0 million, or 6% of the total. – Heathrow handled a total of 482,143 aircraft last year: 479,506 passenger aircraft and 2,637 cargo aircraft, Civil Aviation Authority data shows. This was the equivalent of around 1,317 aircraft a day. – By comparison, the next busiest airport in the UK, Gatwick, handled 265,608 aircraft, or around 726 a day. – The fire at the substation left 100,000 homes without power at the peak of the outage, later reduced to 4,000. 150 people were evacuated from surrounding properties and 200 emergency calls were made.