Mapped: Travel chaos as a UK air traffic meltdown grounds thousands of flights worldwide

• Over 2,000 flights in and out of the UK were canceled after a major air traffic control outage.
• London Heathrow, one of the world's busiest hub airports, was the worst affected.
• Business Insider mapped out 70 diverted flights from the chaos.

Flying into Europe's biggest airport is a crapshoot this week.

More than 2,000 flights were canceled in the UK after the country's air traffic control provider, NATS, said it suffered a "technical issue" on Tuesday afternoon.

London Heathrow Airport, Europe's busiest by passenger numbers and one of the world's most important transit hubs, was the worst affected.

The skies over London were eerily empty as hundreds of thousands of passengers across the country were stuck waiting on the tarmac or in chaotic airport terminals.

Tuesday's pandemonium is causing further disruption because many airplanes and flight crews were left in unexpected cities.

British Airways said on Wednesday morning that its staff worked through the night to build a new flight schedule, but 190 flights still had to be canceled.

According to data from the aviation analytics firm Cirium, 1,746 flights to and from the UK were canceled or did not depart on Tuesday. That's about 30% of the day's schedule.

As of Wednesday lunchtime, another 291 flights had been canceled, representing 5% of the schedule, per Cirium. A typical cancellation rate is between 1% and 2%.

Almost half of Heathrow's scheduled departures were canceled on Tuesday, per Cirium's data. In total, more than 700 flights in and out of Heathrow had been canceled as of Wednesday lunchtime.

Heathrow has one of the most international schedules of any airport globally, with passengers able to fly to over 200 cities in more than 80 countries this month, so the impact of cancellations is global in scope.

Alongside cancellations, Business Insider analyzed Flightradar24 data showing that 70 flights bound for Heathrow were diverted elsewhere on Tuesday.

11 of those ended up at Paris' Charles de Gaulle Airport, while six went to Edinburgh and Frankfurt.

Not pictured in this map is Air Canada Flight 2080, from Halifax, Nova Scotia. Data from Flightradar24 showed the Boeing 737 Max was midway across the Atlantic before it U-turned and diverted to Newfoundland.

Six flights operated by a double-decker Airbus A380 — the world's largest passenger jet— were among the diversions. Half were operated by Emirates, the Dubai-based airline, landing in Birmingham, Munich, and Düsseldorf, instead of London.

Passengers on Singapore Airlines Flight 308 may have had the most confusing ordeal.

The A380 had flown for 13 hours when it was forced to circle over London and turn back. First, it headed east toward Cologne, Germany, but changed directions again and finally diverted to Paris.

This week's problems are the latest in a string of recent issues with NATS that have caused travel chaos in the UK.

Back in August 2023, 700,000 travelers were affected after a software failure shut down NATS' automatic flight-planning system. The event was estimated to have cost airlines, airports, insurers, passengers, and others up to £100 million, or $135 million, according to the UK's Civil Aviation Authority.

Following a spate of delayed flights a year later, Ryanair CEO Michael O'Leary called for NATS' boss to step down. O'Leary said that the incident was "the latest in a long line of cock-ups."

Ryanair executives renewed O'Leary's call in the wake of this week's disruption.

Neal McMahon, Ryanair's chief operating officer, said, "How many more failures do passengers have to suffer before overpaid, failure NATS CEO, Martin Rolfe, accepts responsibility for his repeated mismanagement and resigns?"

In statements posted on X, NATS said it was "truly sorry."

"We know this is hugely frustrating and apologise unreservedly," it added.

Late on Tuesday, NATS said it was assisting airlines and airports to recover.

"This has been a very complex recovery and has created difficulties for the whole aviation network, from which it will take time to recover."

Rolfe was summoned to meet with the UK's transport secretary on Wednesday, The Guardian reported.