FACTBOX-What to know about airlines due to fly into Heathrow Airport on Friday

March 21 (Reuters) - Britain's Heathrow Airport said on Friday that it had begun the process of reopening after a huge fire at a nearby electrical substation wiped out power, shutting down Europe's busiest airport and disrupting the flight schedules of global airlines.

At least 120 inbound flights to Heathrow were diverted to other airports, according to flight-tracking website FlightRadar24.

Here are the top 10 airlines by capacity whose aircraft were set to arrive at Heathrow Airport on Friday.

Here is what airlines are saying about the closure:

• British Airways: "We've been given clearance by Heathrow Airport to depart eight of our long-haul flights today from 7pm. We are now urgently contacting customers to let them know so they can make their way to the airport from 5pm.
  

• United Airlines: We will continue to adjust our flying schedule to London in close coordination with airport authorities. At this time, we expect to operate most scheduled Friday departures to London.
  

• Air India: "London Heathrow-bound AI129 from Mumbai is returning to Mumbai; AI161 from Delhi is diverting to Frankfurt. All our remaining flights to and from London Heathrow, including AI111 of this morning, have been cancelled for 21 March."

• Aer Lingus: "Cancelling all flights to and from London Heathrow Airport until further notice today following the closure of the airport by the authorities."

• Virgin Atlantic: "This has had a significant impact on our flying programme both into and out of Heathrow and all Virgin Atlantic arriving and departing flights are cancelled until midday on March 21, with the rest of today's schedule currently under review."

• Qantas: "Our Singapore-London and Perth-London services were diverted to Paris today, with buses arranged to take customers on to London."

• Scandinavian Airlines System: "All our 12 round trips are so far cancelled to and from Heathrow. We will keep affected passengers informed."

• Ryanair: The airline said in a post on X that it had added up to eight rescue flights between Dublin and London Stansted to rescue passengers affected by Heathrow's closure.

• Singapore Airlines: A spokesperson for the airline said four flights from Singapore to London were affected and four flights from London to Singapore had been cancelled.

• JetBlue: All JetBlue flights to and from Heathrow will be cancelled and additional flights may be scheduled once the airport reopens to accommodate affected passengers.
  

• Delta Air Lines: "Delta has suspended operations to Heathrow Airport and provided customers additional flexibility in rebooking their travel."
  

• American Airlines: "American issued a travel alert, providing additional flexibility for customers impacted by the London Heathrow Airport closure."

Source: Data from Cirium Ascend, company statements.

Note: The seats represent capacity, not ticketed passengers.