WASHINGTON (AFP, REUTERS) - Delta Air Lines said on Monday (Aug 8) some flights are taking off after a power outage caused its computer systems to crash, halting flights worldwide and stranding passengers.
"A Delta ground stop has been lifted and limited departures are resuming," it said.
The airline said customers should still expect delays and cancellations, with long wait times.
"Delta has experienced a computer outage that has affected flights scheduled for this morning," the company said earlier in a statement.
Delta urged travellers to check the status of their flights "while the issue is being addressed."
Delta gave no information on what caused the computer outage.
On Twitter, Delta representatives urged patience and apologised as they dealt with a flood of messages from concerned passengers.
"All our flights are grounded due to the outage," read one tweet.
"We're experiencing a systemwide issue," read another.
Lines of passengers were backing up at Delta ticket counters at US airports.
At Los Angeles, passengers on a flight to New York has to get off their plane and returned to the terminal, NBC News reported, while some people slept near departure gates at Las Vegas.
A vast number of flight delays normally creates a cascading problem that affects airline traffic for days.
Computer outages halting flights are not uncommon. In May a glitch affecting Sweden's civil aviation authority radar site disrupted air traffic throughout that country and grounded flights to and from Stockholm for several hours.
In March, a computer system malfunction forced Japan's All Nippon Airways to cancel more than 100 domestic flights, affecting some 16,000 travellers.
And in mid-August 2015 a computer problem at a regional air traffic control centre delayed hundreds of flights at busy US east coast airports - including those in the Washington and New York areas - for several hours.
A rival US airline, United, suffered computer glitches in May and July 2015 that temporarily grounded hundreds of flights and backed up thousands of passengers.