Hundreds of flights at London's Heathrow and Gatwick airports have been delayed, with disruptions expected to persist into Sunday, as the UK's air traffic control service battles severe thunderstorms. Over 900 inbound and outbound flights have been affected, with some experiencing delays of up to 11 hours and dozens cancelled, according to flight tracking data.

The adverse weather conditions have forced air traffic control to implement safety measures, requiring aircraft to maintain greater separation and avoid affected airspace. NATS, the UK's air traffic control provider, stated that these necessary precautions will impact flight schedules for the remainder of Saturday and overnight.

FlightAware data indicates that more than 474 flights arriving at or departing from Heathrow have been delayed, alongside 439 at Gatwick. The duration of these delays varies significantly, with one British Airways flight from Santiago, Chile, to Heathrow, originally scheduled for a 10:00 BST arrival, now anticipated to land at 21:00 BST.

Eurocontrol, Europe's aviation agency, has mapped significant air traffic control delays concentrated in the airspace between southeast England and northwestern Europe, precisely where the storm clouds are located. While these two major London hubs are heavily impacted, other UK airports have reported minimal disruption.

In an update, NATS explained that severe thunderstorms across southeastern England and Europe continue to disrupt flights. "To ensure the safety of the travelling public, aircraft need to avoid affected areas and be spaced further apart, which limits the number of flights that can operate safely," a spokesperson said. They acknowledged the frustration caused by the delays and assured that efforts are underway with airlines and airports to minimize disruption.

While the forecast for UK airspace on Sunday appears more favorable, NATS warned that further thunderstorms across Europe could still affect flight routes continent-wide. These storms developed following a recent record-breaking heatwave, which saw the UK's highest ever June temperature of 37.3C recorded in Suffolk on Friday.

Passengers have faced considerable inconvenience. One traveler, Adam Joseph, reported being stranded at Venice airport in Italy due to a four-hour-plus delay on his flight to Gatwick. He noted the lack of air conditioning at the airport and expressed concern over potential compensation in light of air traffic control restrictions.

Airport operators Heathrow and Gatwick have advised passengers to verify their flight status directly with their respective airlines before commencing their journeys. The ongoing situation highlights the vulnerability of air travel to extreme weather events, particularly in densely trafficked European airspace.