A recent time-lapse map on social media, painted a stark picture of how a major IT outage crippled air travel across the United States. The culprit? A software issue at cybersecurity firm CrowdStrike which disrupted Microsoft online services, leading to a domino effect. Major airlines like United, American, and Delta were hit hard, as nearly 1,700 flights were cancelled, and many others faced significant delays.

The animated time-lapse map shared by weather analyst, Colin McCarthy (originally posted by Flightradar24.com), showcased the dramatic slowdown of US air traffic. Starting around 8 pm ET on Thursday, the map showed a significant decline in flight activity for airlines throughout the night. In next 24 hours, the expected surge in flights was nowhere to be seen in the map, which is expected on a typically busy travel day, i.e. Friday.

12-hour timelapse of American Airlines, Delta, and United plane traffic after what was likely the biggest IT outage in history forced a nationwide ground stop of the three airlines. pic.twitter.com/wwcQeiEtVe

— Colin McCarthy (@US_Stormwatch) July 19, 2024

Also read | What caused the global Microsoft outage?

The impact wasn’t limited to grounded planes. Cirium, an aviation analytics company, reported nearly 1,700 flight cancellations by 11 am ET on Friday, representing a staggering 6.3% of scheduled US flights. This number ballooned from just 500 cancellations at 6 am ET. Additionally, 37% of US flights on Friday experienced delays exceeding 30 minutes.

The problem wasn’t confined to the US, passengers in airports worldwide faced uncertainty as the IT glitch disrupted communication between aircraft and ground personnel, including air traffic control and airline staff. This led to chaos, with passengers relying on Google searches for flight information instead of airport monitors. In some cases, airlines even resorted to issuing handwritten boarding passes.

While some airlines eventually resumed flights, the disruption underscored the critical need for robust cybersecurity measures to protect the aviation industry from such outages crippling global operations.