Updated 6:25 p.m. ET with more cancellations

Delta says it canceled 680 flights Tuesday as the airline continued to struggle with computer problems.

Our original post continues:

Delta Air Lines announced it was grounding nearly 300 flights Tuesday, a day after a computer outage hobbled the carrier's communication and booking systems and forced it to cancel about 1,000 flights worldwide.

Tens of thousands of passengers were stranded on Monday.

In a statement, Delta said the additional cancellations were to allow the carrier "to reset the operation and get crews, aircraft and other operational elements in place to take care of customers."

Dave Holtz, senior vice president for Delta's Operations and Customer Center, said the company was doing everything "to return our operation to normal reliability."

"We were able to bring our systems back on line and resume flights within a few hours yesterday but we are still operating in recovery mode," Holtz said in the statement.

As The Two-Way reported Monday, Georgia Power, the utility that serves the Atlanta region where Delta is based, tweeted that "Delta experienced equipment failure overnight." The utility provider also said it was working with the carrier to help make repairs.

Delta said Monday that it was looking into what caused the system outage.

In a video posted Monday, Delta CEO Ed Bastian apologized for the inconvenience and offered systemwide waivers to travelers. Delta said it would provide $200 vouchers to all customers who had a flight canceled or experienced a delay of more than three hours.

As The Wall Street Journal reports, the outage likely will cost Delta millions of dollars:

"The meltdown highlights the vulnerability in Delta's computer system, and raises questions about whether a recent wave of four U.S. airline mergers that created four large carriers controlling 85% of domestic capacity has built companies too large and too reliant on IT systems that date from the 1990s. Delta merged with Northwest Airlines eight years ago.

"These systems — which run everything from flight dispatching to crew scheduling, passenger check-in, airport-departure information displays, ticket sales and frequent-flier programs — gradually have been updated but are still vulnerable, IT experts said."

NPR's David Schaper tells our Newscast unit that Delta is just the latest airline to suffer from computer-related complications:

"Just a couple of weeks ago, Southwest Airlines canceled more than 2,000 flights after a faulty router knocked out part of its systems. Computer failures have forced United and other airlines to cancel flights in recent months, too.

"Experts say the airlines are struggling to merge and upgrade their IT infrastructure to keep pace with rapid growth."

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