A fire near London's Heathrow Airport sparked a "seismic disruption" to global air travel on Friday as flights were cancelled and passengers left stranded amid warnings of days of disruption to come.
Heathrow was declared shut for all of Friday after the early-morning fire at an electricity substation knocked out power at Britain's biggest airport. More than 1,000 flights were affected, scrambling travel plans for tens of thousands of people including passengers in the UAE.
Passengers were told not to travel to Heathrow as the closure paralysed one of the world's biggest travel hubs. About 120 flights already in the air either turned back or landed in countries such as France, Ireland or the Netherlands.
London Mayor Sadiq Khan said the disruption could stretch "over the coming days" as crews and flight schedules are knocked off course around the globe. Heathrow said on Friday afternoon that the airport’s back-up energy systems were providing limited power, but there was no clarity on when flights would resume.
All customers due to fly over the weekend will be offered a free rebooking for a later date, Heathrow said. It said it was "working hard to review our long-haul schedule as well as the implications for our schedule for tomorrow and beyond".
Police said there was "currently no indication of foul play" after the fire knocked out a substation and a back-up generator. They said they were keeping an "open mind", and counter-terrorism detectives were leading inquiries because of the significance of the case.
The government said it would "look harder" at how airports can withstand shocks. However, Heathrow said that as an energy consumer on the scale of a small city it could not possibly have back-up power for all its operations.
Diesel generators and emergency power supplies "all operated as expected" but were only ever designed to allow for safe landing and evacuation, not to run the whole airport, Heathrow said. It said it would "take time" to restore power to all affected ar
'Distress and disruption'
Prime Minister Keir Starmer said the chaos was causing "distress and disruption", after the fire cut power to more than 60,000 customers early on Friday. The airport said it had suffered a "significant power cut" due to the blaze at the electrical substation.
“To maintain the safety of our passengers and colleagues, Heathrow will be closed until 23h59 on 21 March," the airport said. "We expect significant disruption over the coming days and passengers should not travel to the airport under any circumstances until the airport reopens."
Some passengers were left confused by messages from airlines telling them their flight was still running. Elvina Quaison, who planned to fly from London to Dubai, said a message at 8am told her she could "go ahead as normal", but in fact there was no way through at Heathrow.

British Airways said it was working as quickly as possible to update passengers "on their travel options for the next 24 hours and beyond", hinting the disruption could stretch beyond Friday. Virgin Atlantic asked people not to phone due to high call volumes, saying they should await details of a rebooked flight by email.
Aviation consultant John Strickland said that even if there was no further disruption it would take days to recover as crews and aircraft would not be in the right place. “With nothing possible in and out of the airport today, that’s a massive dislocation to have to recover from," he said.
"Once an aircraft is in the wrong place with the crew, if you’re away from home you don’t have another crew to suddenly bring the plane and the passengers back. You’ve got to wait until that crew has taken its rest, which is always required after a duty period.“
He likened the disruption to what happened after the September 11 terrorist attacks in 2001, when flights were grounded across the US. He said: “It’s a contained version of 9/11”.
A British government minister, Ed Miliband, said the National Grid power operator had not seen "anything like the scale" of the fire before. He told broadcasters it "makes Heathrow look quite vulnerable, and therefore we’ve got to learn lessons".
How many flights have been diverted?
About 120 aircraft already in the air were diverting to alternative airports or returning to their points of departure, Flight Radar said.
“Heathrow is one of the major hubs of the world,” Ian Petchenik, spokesman for FlightRadar24, said. “This is going to disrupt airlines' operations around the world.”
British Airways has been affected the most, with 30 diversions so far and more than a dozen aircraft still in the air, Flight Radar said. It was followed by American Airlines with 10 diversions and Virgin Atlantic with nine diversions.
London Heathrow is Europe's biggest airport, and the world's fifth busiest airport, handling more than 1,400 flights and 200,000 passengers a day. It is home to major carriers including British Airways and Virgin Atlantic.
Heathrow handled 83.9 million passengers last year, which is about about 220,000 passengers per day. It was the second largest international hub globally after Dubai International Airport, according to data from OAG. It took second place with with 48.4 million seats after DXB with 60.2 million seats.

What is the impact on international flights?
Friday's closure will affect more than 1,000 flights, according to Flight Radar. “Today’s total closure of London-Heathrow will affect at least 1,351 flights to/from LHR. That doesn’t include any flights that might be cancelled or delayed due to aircraft being out of position,” Flight Radar said in a post on Bluesky. This includes 679 scheduled to land and 678 due to take off from the airport, it said.
Heathrow is also one of the busiest destinations for Gulf airlines. Emirates currently operates 42 flights per week between Dubai and the airport, according to its website. Emirates said on Friday said it cancelled three flights to and from London Heathrow: EK001/002, EK029/030 and EK031/032.
“Passengers booked or connecting on to the cancelled flights to London Heathrow will not be accepted for travel,” Emirates said. “We're monitoring the situation closely and will update our customers as the situation develops.”
Etihad Airways said it cancelled four flights between Abu Dhabi and London Heathrow. This includes EY63, EY64, EY65 and EY66.
"Today’s EY61 service from Abu Dhabi to London Heathrow has diverted to Frankfurt Airport (FRA). The EY62 service from London Heathrow (LHR) to Abu Dhabi (AUH) is delayed until further notice," Etihad said in a statement on Friday.
"Disruption at Heathrow is expected to continue over the weekend," the Abu Dhabi-based airline said. It urged passengers to check the status of their flight on the website. Etihad is working closely with guests affected to notify them of the changes to their itineraries."
Dozens of other flights bound for London Heathrow have been diverted to other airports. Australia's Qantas Airways diverted its flight from Perth to Paris, while a United Airlines flight from New York headed to Shannon, Ireland. Another United Airlines flight from San Francisco was scheduled to land in Washington DC instead of London Heathrow.
“The temporary closure of Heathrow, one of the world’s busiest international hubs, represents a seismic disruption to global air travel. The impact is multifaceted, affecting airlines, passengers, cargo logistics, and broader economic activity,” Linus Bauer, founder at BAA & Partners, told The National.
The airport handles 200,000 passengers daily and serves as “a critical connection point for transatlantic and European traffic,” added Mr Bauer. “Any extended closure forces airlines to reroute or cancel hundreds of flights, leading to significant operational costs and logistical challenges.”
What is the knock-on effect on global connections?
Flight diversions to Britain's secondary airports such as Gatwick, Stansted, or even major European hubs like Amsterdam or Frankfurt will create congestion and strain their capacities, Mr Bauer said.
“Passengers face delays, potential misconnects, and increased costs, while airlines struggle with crew rotations, aircraft repositioning, and regulatory constraints,” he added.
The scale of impact on global air travel, airlines and passengers will depend on the duration of the airport's closure. A short-term disruption of up to a day creates “operational headaches but is manageable,” Mr Bauer said.
“A multi-day shutdown, however, forces airlines to rework entire schedules, resulting in billions in economic losses, significant insurance claims, and broader market volatility.”
founder at BAA & Partners
What is the impact on air cargo?
Beyond passenger travel, Heathrow is a major cargo gateway, handling high-value goods, perishables, and time-sensitive shipments.
Disruptions can have “cascading effects” on supply chains, particularly for industries that rely on just-in-time deliveries, such as pharmaceuticals and automotive manufacturing, according to Mr Bauer.
A 'systemic shock' to global aviation
Airlines will prioritise rerouting high-revenue routes, while authorities may implement temporary measures such as lifting slot constraints at alternate airports, according to Mr Bauer.
Meanwhile, governments and aviation regulators will need to co-ordinate closely to limit the impact on passengers and ensure that operations continue. “Ultimately, the closure of Heathrow is not just an airport disruption – it’s a systemic shock to the global aviation ecosystem. The resilience of the industry will be tested, and strategic agility will be key in minimising long-term fallout,” Mr Bauer said.