Delta Air Lines spent Monday recovering from its second computer system meltdown in a little more than five months, though this one was much less disruptive.

The Atlanta airline said about 280 flights were canceled Sunday night and early Monday after an unspecificied systemwide technical issue grounded domestic departures for several hours.

Delta said “essential” information technology systems crashed at about 6:30 p.m. Sunday, and remained down until just before midnight. The airline said operations largely returned to normal on Monday.

Delta’s headaches prompted President Donald Trump to cite the carrier in Twitter posts defending his controversial executive order barring entry into the U.S. by refugees and other travelers from seven predominantly Muslim nations. Trump said the Delta outage caused “big problems at airports” after his order sparked protests at airports across the nation.

A Delta spokeswman said she did not have details on the cause of the system crash, or how many flights or passengers in Atlanta were affected.

A Hartsfield-Jackson International spokesman said about 750 people spent the night Sunday on concourses, and that concessions were kept open late to ensure they had food and drink.

Airlines have been hit by a string of computer outages, causing varying degrees of travel disruption.

United Airlines, based in Chicago, suffered a similar Sunday night outage just a week earlier, as well as one last summer.

Last August, a much more serious failure of Delta's computer equipment shut down its passenger check-in system for days, leading to 2,300 flight cancellations and a $150 million hit to its pre-tax income.

Computer system problems crippled Dallas-based Southwest Airlines for 12 hours in July 2016, leading to long delays getting things moving again.

One expert said Monday that recurring glitches are a sign airlines are having trouble making the switch from legacy computer systems to so-called “virtual” or “cloud”-based systems.

“We see a lot of companies struggling with the digital transformation,” said Jim Melvin, chief marketing officer at SevOne, a Boston company that monitors core information networks for companies such as Verizon, Comcast, EBay and Morgan Stanley.

The new cloud systems — virtual networks of servers that can handle multiple tasks — promise to improve reliability for companies’ core systems, said Melvin. But the outages show that airlines are having trouble keeping their old systems running while they shift to virtual networks on the fly, he said.

“If they don’t get real about this next generation of technology,” he said, “they will be left behind.”

Melvin said the flight cancellations this week could cost Delta more than $50 million from lost passenger revenue and the hit to its reputation.

“That’s all brand impact,” he said.

Delta CEO Ed Bastian, a company veteran promoted to the top post in May 2016, found himself issuing a public apology for the second time.

"I want to apologize to all of our customers who have been impacted by this frustrating situation," Bastian said on the passenger carrier's website. "This type of disruption is not acceptable to the Delta family, which prides itself on reliability and customer service. I also want to thank our employees who are working tirelessly to accommodate our customers."

After the August meltdown, Bastian acknowledged in an interview with the AJC that “our infrastructure is dated, no question,” but added the airline spends about $1 billion a year on technology and had hired new technology executives who were “pulling together the next level of investment.”

“This is an area that we know was in need of investment. We have been investing in it, ” Bastian said at the time. “It’s not an area that we’ve been dismissive of.”

Delta said it is waiving change fees for Jan. 29-30 flights for passengers who re-book travel by Feb. 3. The airline urged customers to check their flights’ status on delta.com or its Fly Delta app.

— Staff writer Tammy Joyner contributed to this report.