The hours ticked by. She and the other passengers finished watching “You’ve Got Mail” and then moved on to “When Harry Met Sally.”

Klein was still stuck on the plane — and her fellow travelers seemed to be restless.

“ ‘It’s hard to see how this ends,’ ” the lady next to me says,” Klein tweeted.

The power outage ended at 11:45 Sunday night, nearly 11 hours after it had begun.

It’s one of the busiest times of the year for the world’s busiest airport, Atlanta’s Hartsfield-Jackson International.

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The outage, which completely crippled the airport’s infrastructure, was caused by a fire in a Georgia Power underground electrical facility, the company said in a statement. The facility reportedly also houses the switch that might have activated backup power.

A total of 1,175 flights were canceled going into and out of the airport, according to Flight Aware, a flight data tracking company. An additional 374 were canceled by 3 a.m. Monday.

Inside the airport, the familiar sound of jets roaring was replaced by repeating emergency announcements, occasionally pierced by a baby’s wails — according to videos, images and stories that poured onto social media from inside locked planes and darkened terminals.

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Among those stuck on a flight was former U.S. transportation secretary Anthony Foxx. “There is no excuse for lack of workable redundant power source,” he tweeted. “NONE!”

Some planes sat on the tarmac for more than six hours, The Washington Post reported. WST-TV reporter Mark Winne posted a video showing more than a dozen of those planes, lined up but not moving, like cars at a drive-in movie.

“The five-hour point is where my patience runs out,” Klein tweeted from the plane at 7:18 p.m. By then, as she reported, the plane had run out of food and water, and the toilets had to be dumped to avoid overflowing.

“We are still stuck on planes,” comedian Brian Moote tweeted about 5 p.m. “This place is screwed, if you had a flight tonight, you don’t now. Stay home.”

After several hours, they began deplaning — often onto the tarmac itself, as Steven Jones of San Diego showed in a video on his Instagram account.

At 10:12 p.m. — nearly 10 hours after the power outage — Atlanta Mayor Kasim Reed tweeted that all planes had been deplaned.

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Videos from inside the airport painted a dire picture.

Natalie Seitz, 23, of New York posted a video on Twitter about an hour and a half after the airport announced it had lost power. “An emergency has been reported in the building,” a mechanical voice kept saying, before instructing passengers to “stand by for further instructions,” as emergency lights flashed.

“You walk around and hear people talking to each other and jokingly yelling at the PSA system when it repeats the same thing,” Seitz told The Post.

Some areas of the airport were so dark that people used the flashlight function on their smartphones to get around.

In other areas, bored passengers waited in long lines or simply sprawled out on the slick airport floor, waiting in the semidarkness. Many were fed by the fried chicken restaurant chain Chick-fil-A, which broke its tradition of being closed on Sundays to feed hungry travelers. Reed thanked the company in a tweet, noting that “We have provided 2,000 meals so far.”

Some passengers complained of a lack of emergency response during the outage, which was especially problematic for those who used a wheelchair to get around.

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Laura Ward, who was stranded in the airport, told the Associated Press she was shocked by the lack of “any emergency management, like police officers” or “firefighters.”

“So we were literally carrying old people down the escalators and up escalators and carrying wheelchairs, and my heart was like racing because I’m scared for these people’s lives,” Ward said.

“Where is Atlanta police?” she added.

Rutia Curry, a fellow stranded passenger, told the AP, “They had these elderly people and handicapped people lined up in wheelchairs,” some 20 of them, who couldn’t do anything “because they couldn’t get down the escalator.”

“People are helpless,” Curry said. “It’s a nightmare.”

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Moote posted a video on Twitter about 7:20 p.m. showing TSA agents carrying wheelchairs up the stairs.

Many passengers complained about the lack of direction given by airport officials.

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“This has been very bizarre,” Olivia Dorfman, a stranded passenger, told the Atlanta Journal-Constitution, before adding, “No one seems to know what they’re doing.”