Bizarre theory emerges that FAA grounded all flights as 'UFO' spotted over South America

Thousands of passengers have been caught up in travel chaos after the Federal Aviation Administration (FAA) grounded flights across the US, but an unusual theory about what really happened has started circulating online.

The extraordinary shutdown, which lasted more than four hours on Friday (November 13), has prompted speculation among some social media users that it could have something to do with an alleged UFO sighting over South America.

One user questioned whether the supposed incident could explain the decision to suspend flights in the US asking: "Is that why they would suspend flights in the US? Just asking."

Others have also weighed in, with one person suggesting that something similar had happened in Querétaro, Mexico, although they admitted they hadn't personally witnessed anything.

Another commenter took a more tongue-in-cheek approach, joking that Elon Musk had been flying around in his spaceship with a laser beam.

And while some people appear convinced there could be more to the story, the official explanation for the aviation disruption is considerably less extraterrestrial.

The FAA issued a nationwide ground stop at around 4pm EST (9pm GMT) on Friday, November 13, citing a telecommunications outage affecting air traffic control centres.

The decision meant that departing flights across the country were temporarily halted, while aircraft already in the air were allowed to continue to their destinations.

Transportation Secretary Sean Duffy later explained that problems with the country's ageing air traffic control infrastructure had affected radar and communications systems.

Officials said the issue was serious enough that they had to stop departures as a safety precaution.

The ground stop was lifted at around 8.15pm EST, but the disruption was far from over.

According to FlightAware figures reported by the Los Angeles Times, thousands of flights had been delayed or cancelled, with passengers facing further disruption as airlines attempted to get their schedules back on track.

By Saturday morning, November 14, airports across the US were continuing to report cancellations and delays.

New York's JFK airport, Chicago's O'Hare and Atlanta's Hartsfield-Jackson were among those experiencing significant disruption.

The knock-on effects have also extended beyond the US, with airports in Europe and Asia reporting delays and cancellations affecting services travelling to and from America.

Sean Duffy warned that the ripple effects could continue for days, as airlines work through the backlog.

Despite the theories circulating online, officials have not linked the ground stop to extraterrestrial activity, and there is no evidence that a UFO sighting had anything to do with the FAA's decision.