An airport employee punched a baby-carrying passenger in the face at the airport in Nice, France. (Arabella Arkwright)

It had all the makings of a modern-day airport nightmare: a 13-hour delay, more than 100 cranky and exhausted passengers, and babies running out of formula and diapers.

And that was before an airport employee punched an infant-carrying customer in the face.

A photo of the latest case of air-travel misery shows the exact moment the frustrations of easyJet Flight 2122 boiled over: the outstretched arm of a uniformed airport worker connecting with a man’s cheek, inches away from a baby.

The man who was struck was one of the passengers scheduled to depart from Nice, France, late Sunday morning. The plane was to land at Luton Airport, just outside of London, two hours later. Instead, a mechanical problem with the plane caused a half-day delay.

Worse, said another passenger, Arabella Arkwright, easyJet personnel either didn’t have answers or didn’t communicate them to the passengers languishing in the waiting area. Employees distributed food vouchers, but they barely covered the cost of a muffin at a nearby Starbucks, Arkwright told The Washington Post.

As the hours ticked by, the stranded passengers could hear calls for other easyJet flights that were going to Luton Airport.

It reached a boiling point at the 13-hour mark, sometime before midnight. Passengers were finally told that they finally board, then there was a delay at the aircraft’s door, Arkwright said. They were stuck on a jet bridge for a half-hour before trudging back into the terminal.

A man holding a baby and a cellphone approached an employee for Samsic, a contractor that assists customers at the airport, for more information.

Voices were raised.

Passengers stared.

“It was just the straw that broke the camel’s back,” Arkwright told The Post on Monday. “The easyJet employee lifted his hand first and pushed the mobile phone out of the man’s hand. You could see it go flying. The man pushed him back, like he was protecting the baby.”

“And then the [worker] just whacked him,” said Arkwright, who captured the punch on her smartphone camera, then tweeted the photo at British media outlets and the budget airline.

On social media, people debated who, exactly, was the aggressor.

In a video obtained (and slowed down) by the Sun, the man with the baby and other passengers were heard angrily complaining to the airport worker.

Arkwright, who witnessed the altercation along with her husband, said the worker turned a verbal confrontation into a physical one when he slapped the phone out of the complaining man’s hand.

The man with the baby appeared to shove the worker. Then came the punch.

“It was a verbal thing, and then the … employee knocked the phone. It went flying; you could hear it,” Arkwright said.

Arkwright said that she and other passengers were outraged, but not entirely surprised that the situation had devolved to violence.

Afterward, the airline went into damage-control mode. The puncher, easyJet said in a statement, was not one of their employees. He worked for “special assistance provider” Samsic. The airline said it was trying to get to the bottom of the situation.

Samsic did not return a message seeking comment.

It’s unclear what happened to the worker. Both he and the man he punched were escorted away by airport security guards.

The man with the baby returned with a fresh welt on his face and received applause from the other passengers, who were now seated and ready to take off, according to Arkwright.

But Arkwright said she was still incensed at easyJet. Even though the employee wasn’t on the airline’s payroll, he was interacting with easyJet’s customers. And, she said, company managers were nowhere to be seen as the customer service problems mounted all day.

“We’d been trying to get information out of them all day long,” she said. “I’ve seen their statements. They said they kept people informed. We had to keep going up with questions. On their app they had one thing. On the board they had another thing. On the website they had another.”

Two weeks ago, an unaccompanied minor was booted from an overbooked easyJet flight on his way to visit relatives in Toulouse, France, The Post’s Lindsey Bever reported. Airline officials left the 15-year-old alone at the gate as the plane took off; easyJet officials apologized and pledged to investigate.

Elsewhere, during this never-ending season of misery for air travelers and airlines, families have been booted from flights over a birthday cake and a toddler kicking a passenger’s seat. Other airline incidents have included bitingracist and politically charged rants and smashed wine bottles.

Earlier this year, David Dao’s removal from a United Airlines plane sparked a public-relations nightmare for the company. In that incident, a United official told passengers that they needed four people to give up their seats to accommodate off-duty crew members. When no one volunteered, the airline randomly selected four people. Three left without incident. Dao wouldn’t budge.

In the ensuing struggle with officers, Dao fell and hit his mouth on a seat’s armrest. His lawyer said he broke his nose and lost two teeth. Dao went limp, and a video captured him bleeding from the mouth as officers dragged him off the plane.

United Airlines said a man wouldn't give up his spot on a flight. According to witnesses, he was pulled screaming from his seat by security and back to the terminal at Chicago's O'Hare International Airport. (The Washington Post)

On April 21, an American Airlines employee was accused of upsetting a woman carrying a baby to the point of tears, then getting involved in a heated exchange with a man who came to her defense, according to The Post’s Amy B Wang.

Arkwright, at home a day after her ordeal in Nice, said she was thinking about the recent spate of airline mishaps when she wrote a letter to easyJet chief executive Carolyn McCall.

Arkwright said her biggest gripe wasn’t with the airline’s front-line employees, but with managers who’d allowed the situation to devolve by not communicating.

“In short, the whole saga was a disgrace; the problem is a management one and, yes, that is YOUR responsibility,” she wrote. “How much more inept can you be before your shareholders as well as your customers get seriously angry?

“Information was contradictory all day as the departure time got put back and back — so as not to get people angry at the outset and/ or because there was no f‑‑‑ing Plan B.”

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