London's Heathrow Airport​, one of the busiest airports in the world, was shut down by a power outage caused by a fire at an electrical substation.

Heathrow’s chief executive has defended the airport’s response to the power outage and shutdown that sparked global travel chaos, apologizing to stranded passengers and confirming the airport is “operating as normal” Saturday.

Officials and travelers are calling for an investigation into not only how the blaze started, but how it was able to cause such a large disruption to global travel.

London's Heathrow Airport reopened on Saturday after a power outage at one of the world's busiest airports the previous day caused widespread chaos and cancellations.

Flights to and from London’s Heathrow Airport were canceled Friday after a fire at a nearby substation knocked out power to Europe’s busiest airport, disrupting travel plans for hundreds of thousands of people around the world.

The blaze forced Britain’s largest airport to cancel or divert more than 1,000 flights on Friday and removed a linchpin of global air travel. Counterterrorism police were investigating the cause of the fire.

Heathrow Airport in London announced it will be closed Friday after a large fire at a nearby electrical substation caused a power outage.

A fire at a nearby substation knocked out the airport's power. At least 1,350 flights were affected, FlightRadar 24 said, and the impact was likely to last several days.

(Maja Smiejkowska/PA via AP) A British Airways plane takes off as Heathrow Airport slowly resumes flights after a fire cut power to Europe’s busiest airport in London, Saturday, March 22, 2025.(AP Photo/Kirsty Wigglesworth) In this photo taken from video ...

The UK Secretary of State for Energy Security and Net Zero Ed Miliband announced Saturday that he is ordering an investigation into the substation fire.