(Bloomberg) — Airlines around the world experienced disruption on an unprecedented scale after a widespread global computer outage kept aircrafts on the ground and created chaos at airports just as the busiest summer vacation season gets underway.

In total, there were more than 1,300 flights globally that had been canceled amid an IT-system meltdown that hobbled communication between aircraft and ground-control staff. The disruption hit travellers on a particularly active day — the UK, for example, was preparing for the highest number of daily departures since October 2019, according to aviation data provider Cirium.