Delta Is Now Under Investigation as the Airline Continues to Cancel Flights After Mass Outage: 'Lost a Customer for Life' On Tuesday morning, Delta canceled more than 12% of its total flight schedule.

Most systems are back to normal for the many industries and businesses affected by Friday's CrowdStrike update that caused a mass outage of Microsoft Windows-run devices.

Except for Delta Airlines, where the drama appears far from over.

Related: CrowdStrike CEO Responds to Its Update Largest IT Outage in History

On Tuesday, U.S. Transportation Secretary Pete Buttigieg announced that the DOT has opened an investigation into Delta and the chaos after the outage to "ensure the airline is following the law and taking care of its passengers during continued widespread disruptions."

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. We will follow up. https://t.co/Noj5A5hE8w

— Secretary Pete Buttigieg (@SecretaryPete) July 23, 2024

Between Friday and Monday, over 1,000 flights were canceled by the airline, leaving many stranded and even more without their luggage.

As of Tuesday morning, Delta had already canceled another 451 flights (12% of its total flight schedule for the day), and it continues to go up. The number of delayed flights was 656 as of press time.

On Sunday, Delta CEO Ed Bastian penned an email to customers, blaming the outage for affecting crew tracking software, despite other airlines getting back up and running.

"One of our crew tracking-related tools was affected and unable to effectively process the unprecedented number of changes triggered by the system shutdown," Bastian wrote. "Our teams have been working around the clock to recover and restore full functionality."

The New York Times is reporting that Delta is banning unaccompanied minors from flying during the continued chaos to "protect" minors from potentially being separated from their families and caregivers during delays or cancelations.

Hundreds took to social media over the weekend and early this week to complain about the mass outages and cancelations.

Atlanta airport is jam-packed. Mothers w/ small children on the floor in the terminal. Line for customer service is 1/2 mile long. No rental cars. Few hotel options. People've been stuck here 3 days.

If there weren't bigger national news- @Delta CEO would be dragged to testify. pic.twitter.com/tGSRGyxYG5

— Cole T. Lyle (@ctlyle1) July 22, 2024

Delta has completely dropped the ball on this.

My family and I have been stranded at Atlanta airport for 4 days now.

0 car rentals
0 hotels (was able to get one through a rewards program 25 minutes from the airport for tonight)
0 available flights
4-5 hours in line to even… pic.twitter.com/O6GRssOrdk

— Multifamily Madness (@MultifamilyMad) July 22, 2024

For the last decade I've flown first class @Delta for every single flight.

Never again.

Y'all just lost a customer for life.

Horrible customer service. Cancelled flights with no reimbursement. No answers from anyone.

RIP, @Delta, you're dead to me. pic.twitter.com/ln7AJAr0j1

— Jason Helmes (@anymanfitness) July 22, 2024

Welcome to Day 5 of Delta's meltdown.

400 flights canceled and counting as the sun rises. Another 244 delayed.

That's better than this time yesterday … but still unacceptable.

It will take at least several more days before this is completely fixed. Buckle up.

— Kyle Potter (@kpottermn) July 23, 2024

Buttigieg said that he spoke to Bastian to ensure customers are compensated and rebooked.

"I have made clear to Delta that we expect the airline to provide prompt refunds to consumers who choose not to be rebooked, and free rebooking and timely reimbursements for food and overnight hotel stays to consumers affected by the delays and cancellations, as well as adequate customer service assistance to all of their passengers," Buttigieg said, per ABC News. "No one should be stranded at an airport overnight or stuck on hold for hours waiting to talk to a customer service agent."

Bastian told customers in an email that those affected would receive vouchers for meals, hotels, travel, and DeltaSkymiles.

Related: Delta Estimates $100 Million Loss Due to Olympics

Earlier this month, the airline reported its Q2 2024 earnings, estimating a $100 million revenue loss this summer due to low travel volume to France during the 2024 Summer Olympic Games.

Delta did not immediately return Entrepreneur's request for comment.