American Airlines resumed flights after a one-hour suspension on Tuesday due to a technical issue affecting plane release systems.

The nationwide halt ended just before 13:00 GMT, as confirmed by the Federal Aviation Administration (FAA).

The disruption occurred on one of the busiest travel days of the year, Christmas Eve.

The airline attributed the problem to a “vendor technology issue” and announced “all hands on deck” to minimize further disruptions.

“We sincerely apologize for the inconvenience this morning,” the airline stated.

“Our team is working diligently to get customers where they need to go as quickly as possible.”

Departure boards at major US airports still show delays of up to two hours. However, Flightradar24 indicates planes are taking off again at several major US hubs, with most flights departing on time.

Passengers reported on social media about being stuck on the tarmac or at gates due to the outage. Some passengers were also told to disembark from their planes.

In a video posted by a CBS reporter in Fort Lauderdale, Florida, a gate agent announced that a flight to Philadelphia was beginning to board. “The system is slowly coming back,” the agent announced.

In July, American Airlines and other major operators grounded flights across the US due to communication issues caused by a global IT crash. That failure, which also affected banks and emergency services, was caused by a faulty software update from cybersecurity firm Crowdstrike.