London Heathrow is one of the world's busiest airports
AFP

Heathrow is back to being "fully operational" following a major fire at a nearby electricity substation, which led to the airport's shutdown and caused chaos in global air travel, leaving 250,000 passengers stranded.

By Saturday morning, the airport had regained power, and the terminals were lively, with flights taking off and landing. Heathrow, Europe's busiest airport, resumed operations more quickly than expected following the abrupt shutdown on Friday.

British Airways canceled nearly 80 flights on Saturday, following the grounding of almost its entire schedule on Friday.

Sean Doyle, CEO of British Airways, the largest operator at Heathrow, warned that the "incident will have a major impact on both our airline and our customers for several days," with travel disruptions expected to continue. He referred to the situation as "unprecedented."

The backlog of flight disruptions may take several days to fully resolve, as airlines continue to manage the aftermath. They are working to adjust schedules, reconfigure flights, and accommodate affected passengers. Delays and cancellations are likely to persist as airlines make efforts to restore normal service, and it will take time for the operations to get back on track.

The airline announced that it expects roughly 85% of its scheduled flights for Saturday to operate as planned. However, this still means that around 90 flights could face cancellations or severe delays, depending on how the situation unfolds throughout the day.

The airport reopened faster than anticipated, going against its earlier predictions of an extended closure. Heathrow had initially announced it would remain closed until 11:59 p.m. on Friday, with disruptions possibly extending for several days. However, by Friday evening, the airport had already resumed some flights.

Willie Walsh, the head of the global airlines body IATA and former British Airways CEO, criticized the airport, calling it a "clear planning failure." Walsh, who has been a long-time critic of Heathrow's congestion, expressed frustration over the situation, pointing to the airport's lack of preparedness.

Counter-terrorism police have been leading the investigation into the cause of the fire, although the London Fire Brigade has stated that it is being treated as "non-suspicious."

In the meantime, police confirmed that, after an initial evaluation, they were not treating the incident as suspicious. However, their investigation is still ongoing. The London Fire Brigade stated that their focus would be on the electrical distribution equipment, which is believed to be the source of the fire.