But the airline also warned that heavy spring break travel means there are few open seats for rebooking, leaving limited options for passengers whose flights were canceled.

Long lines for rebooking, baggage assistance and check-in at Delta counters filled the terminal in Atlanta on Friday morning, two days after the thunderstorm that triggered the flight disruptions.

What To Do the Minute Your Flight is Canceled

For the second night in a row, weary travelers spread across the floor of the Hartsfield-Jackson terminal to try to sleep overnight after their flights were canceled Thursday. Some said they had been stuck on planes until 2 or 3 a.m. before a final flight cancellation left them stranded.

Delta’s systems were also overtaxed: Many travelers struggled to get information or rebookings from Delta’s app, its website or from its customer service phone line.

Thousands of people stood in line for hours in the concourses and in the terminal to try to get rebooked on flights back home or to their destinations.

Delta said those whose flights are canceled and who don’t travel are entitled to refunds. The airline is also waiving certain change fees for passengers affected by the disruptions who want to reschedule their flights.

“It looks like a disaster zone,” said traveler Shadow McKnight, who was trying to get home to Starkville, Mississippi. “Just how everybody is piled up on every available surface... I’ve never seen it like this.”

Some stranded passengers were still at Hartsfield-Jackson International Airport on Friday, April 7, 2017. HYOSUB SHIN / HSHIN@AJC.COM HYOSUB SHIN / AJC/hshin@ajc.com

McKnight was scheduled to fly back to the Memphis airport Thursday evening at around 8 p.m., but said her flight was delayed until 10 p.m., then 11 p.m., then midnight. “And then they cancelled it,” she said, because the crew wasn’t able to get to Atlanta on their own flights.

“I was like, ‘This is just crazy,’” McKnight said, seeing the line stretching down the concourse for customer service. A Delta agent at the gate helped her and a few other passengers get rebooked.

To get to Memphis would require waiting until Saturday and spending another night in Atlanta. McKnight tried to get a rental car but found none available.

Instead, her husband will drive from Mississippi to Atlanta to pick her up, then head to the Memphis airport to pick up her car before going back to Starkville.

“At this point, I just have to get home,” said McKnight, a furniture designer who is trying to return home from a business trip to Louisville. She spent the night in the terminal. “I kind of just walked around for a while, then found a table and laid my head down.”

McKnight said she is understanding of the challenges that Delta has faced.

“It was just a series of unfortunate events,” McKnight said. “Nothing was in place to work out easily for them. I’ll fly Delta again. Everybody has bad days, right?”

Delta lines at Hartsfield-Jackson on Friday morning, April 7, 2017.

Traveler Farzad Saghian said his flight back home to New York after a business trip was scheduled to depart at 8:30 p.m. Thursday, then was delayed until 11:30 p.m., 12:30 a.m., then 1:30 a.m.

“First they didn’t have a captain, then they didn’t have a crew” of flight attendants, Saghian said. “We waited until 3:30 (a.m.) until they just said yes, it’s canceled.”

Everyone was frustrated, he said: “They kept on giving us hopes: ‘Don’t worry, it’s not going to cancel.’

“I always fly Delta everywhere,” Saghian said. “For the past 20 years I’ve been with Delta. So I’m with them. I understand. It’s the weather. But they could have been a little more courteous. People were frustrated. There were babies in people’s hands.”

Saghian, who travels to Atlanta five times a year, had been in the airport for 14 hours by Friday morning and expected to wait another several hours for his rescheduled flight.

“It’s always busy, but I have never seen this airport like this,” Saghian said. “It was like a madhouse.”