Delta is still melting down. It could last all week

As of 8:30 am ET the Atlanta-based airline had canceled 420 flights, and Endeavor Air, its regional carrier that feeds its system under the Delta Connection brand, had canceled another 18 flights. The cancellations follow more than 1,250 flight cancellations Monday, and 4,500 flights from Friday through Sunday between Delta and Delta connection.

There were more than 400 Delta and Delta Connection listed as delayed by FlightAware. The canceled flights by the two carriers represented nearly 70% of all flights within, to or from the United States that have been canceled on Monday, according to FlightAware. No other US airline had canceled one tenth as many flights.

The problems prompted the Transportation Secretary Pete Buttigieg to announce the Department of Transportation would be starting an investigation to make sure Delta is following the law and treating passengers fairly. He asked passengers with complaints to contact the Department of Transportation.

“While you should first try to resolve issues directly with the airline, we want to hear from passengers who believe that Delta has not complied with USDOT-enforced passenger protection requirements during the recent travel disruptions,” he tweeted. “We will follow up.”

Delta did not immediately respond to a request for comment on the DOT investigation.

The problems stemmed from a software update issued late Thursday night by cybersecurity firm CrowdStrike that crashed Windows software. A cascade effect caused problems throughout the global airline industry last Friday.

Although most airlines were able to recover and resume normal operations by the end of the weekend, Delta has been unable to fix problems with its crew tracking system, leaving it unable to find the pilots and flight attendants it needed to fly its planes.

The problems will continue for at least a few more days, warned Rahul Samant, the company’s chief information officer, in a message to Delta employees Monday.

“So we’re optimistic we’ll get it done,” Samant said in the video message along with CEO Ed Bastian. “There will be some things as Ed said, that we will do today, tomorrow to get to a better place by the end of the week.” He said the IT staff is working “feverishly” and “around the clock” to fix the problem.

Frustrated passengers and crews

The problems left tens of thousands of frustrated Delta customers stranded and unable to return home. Many of them booked other flights that were subsequently canceled as well. A lack of hotel rooms forced many to sleep in airports and wait for hours on hold trying to get through to Delta in an often-futile effort to find a flight.Delta crew members are dealing with similar frustrations. Many have been left stranded in airports far from their bases and homes, unable to be placed on flights because Delta has been unable to locate crews and place them on planes. Some Delta crew members also are unable to get hotel rooms and are sleeping at airports. And airport employees are contending with angry, frustrated customers who don’t understand why their flights are being canceled when crew members are available.

This week, Delta remained in the dark about the whereabouts of its crew members. Crew members who logged on to the company’s computer system to sign up for flights received prompts and questions that included: “Please enter below what airport code you are closest to,” “What is your current status?” and “Please describe your current location.”

A person familiar with the airline’s operations allowed CNN to see screenshots of the prompts. Delta declined to comment on the questions it was asking crews.

To help fix its staffing problems, Delta is offering crew members premium pay, as well as additional assurances they will be able to travel back to their homes at the end of their work period, according to the screen shots viewed by CNN. The premium pay and assurances would be in place through Friday, another sign the staffing problem may not be fixed for several more days. Delta also declined to comment on these offers to crew members.

Costs at $163 million - and climbing

The service meltdown will cost Delta, both in terms of its reputation and in dollar costs. The meltdown has already cost the most profitable US airline about $163 million through Monday, according to an estimate from Savanthi Syth, airline analyst for Raymond James.

That estimate comes from lost revenue and is likely to climb once additional pay for staff and reimbursements for customers are added in. Although the problems Tuesday the remainder of the week are not as bad as they had been the last four days, the additional flight cancellations will add to those losses.

Delta has prided itself on its on-time performance and customer service. Earlier this month its bragged in its earnings report that it achieved industry-best completion factor and on-time performance, and operated 39 cancellation-free, brand-perfect days. This meltdown is doing some damage to that reputation that will take time to repair.

After a similar service meltdown at Southwest Airlines during the year-end holiday travel period in 2022, the airline canceled nearly 17,000 flights, or about half of its schedule, stranding more than 2 million passengers over an 10-day period. That cost it nearly $1.2 billion between the fourth quarter of that year and the first two months of 2023. In additional to customer compensation, the airline faced additional labor costs and lost revenue that continued into February. In addition it was hit with a $140 million fine from the Department of Transportation.

Delta’s service black eye could also cause it to lose some future bookings from frustrated customers. This past weekend was the busiest travel period of the summer with 90% of the seats booked. That has made it difficult for Delta to find other flights for those customers whose flights have been canceled. Even if Delta was operating all of its flights normally, it would take days to accommodate all its angry, stranded passengers.

Rows and rows and rows of luggage

Getting those passengers reunited with their checked baggage is going to take many more days beyond that.

United Airlines was also hit hard by the computer problem, with more than 1,000 canceled flights, although it was back to near-normal operations on Monday with only 69 cancellations for its mainline operations. In a note to staff CEO Scott Kirby said that the airline’s 26,000 computers affected by the problem had all been fixed and its operations had been normal for the last 24 hours. He said some passengers had yet to be reunited with their baggage, and United is using FedEx to deliver the bags to some of them.

At Atlanta’s Hartsfield-Jackson International Airport, Delta’s headquarters and largest hub, thousands of pieces of luggage are lined up on the floors of baggage claim. The bags made it to the world’s busiest airport but, through delays and cancellations, their owners either have not yet arrived or arrived on a different plane.

Delta employees from all different departments and roles across the company were supplementing efforts to help passengers who made it to Hartsfield to find their bags.

Arthur Ginolfi, who had flown into Atlanta for a Global Business Travel Association convention after two trips to the airport in Philadelphia over the weekend, was one of those picking up a bag that had arrived on a different flight than he did.

“This is the worst experience I’ve ever had in my 35 years of business travel,” he said. “There are lines that were unacceptable, there were people that were frustrated. I saw and I heard a lot of sad stories.”

He said he thinks Delta needs to be offering more compensation than he’s gotten from the airline so far.

“I had to pay for parking for 12 hours, I had to pay for food, I had to pay for tolls,” he said. “I deserve more pros than a $24 gift card.”

This story has been updated with additional context and developments.

CNN’s Isabel Rosales contributed to this report.