Others closed their windows, grabbed their loved ones and prayed. Thousands of feet below in a Denver suburb, people on the ground ran to shelter to dodge debris suddenly plummeting to the earth.
The pilots issued a mayday call and, after turning back to the airport, landed the Boeing 777-200 plane safely. Remarkably, there were no reports of injuries either in the air or on the ground. Still, interviews with passengers show the incident provided a huge scare for everyone involved.
Here’s how those in the air and down below said they reacted during those tense moments.
‘There was a big boom’
Travis Loock, a passenger on Flight 328, told CNN it was about 20 minutes after takeoff for Honolulu that he heard a boom.
“There was a big boom and the kind of sound you don’t want to hear when you’re on the airplane,” Loock, who was flying with his wife, said in a phone call. “And I instantly put my shade up, and I was pretty frightened to see that the, the engine on my side was missing.”
“We were just glad we weren’t over the ocean, because that’s where we were heading,” he said.
Loock said he could sense the fear on the plane, but everyone was “very calm.”
“A lot of people couldn’t see the engine on that side, right, so I was a little more freaked out because I could see it, and I knew that was not right,” he said.
When Bob Brown heard the explosion, he looked out his window, saw the damage to the engine and took out his phone to film it.
“We looked at each other, my wife and I, held hands, and just wished our kids that we’d see them again,” he told KCNC.
‘Let’s just pray’
Vena said the crew’s professionalism calmed them, but he said he was still worried.
“There was no panic among the crew, there was no panic among the passengers,” he said. “I just worried about my kids because they’re not with us so they’re away at school and this is our first vacation alone in 21 years.”
“Initially I think it was fairly panicked,” Dan Smith of Portland, Maine, told KCNC, “but I think people did a good job of calming down.”
Danielle Thomas, who lives in Honolulu, praised the flight crew for their demeanor.
“I think the pilots had a huge hand in making everybody feel safe and comfortable,” she told KCNC.
Troy Lewis said he felt confident they’d make it back safely.
When the plane landed safely, people cheered before exiting.
Once back safely on land, Loock said he calmed his nerves and prepared for the rest of the journey.
“We’re having a cocktail,” Loock said. “And, yeah, we’re going to try it again. We’re going to try it again. The odds are with us this time.”
He was not alone in wanting to continue his journey. United said in a statement a majority of the passengers have taken another United flight to Honolulu while “those who did not wish to travel with us this evening were provided hotel accommodations.”
What those on the ground did
While those in the air stressed about the landing, those on the ground looked up to see debris falling from the sky.
“But as soon as I open the door, I go, ‘that is the front engine of a plane,'” Klements said.
Kieran Cain told CNN he was playing with his children at a local elementary school when a plane flew over and they heard a loud boom.
“We saw it go over, we heard the big explosion, we looked up, there was black smoke in the sky,” Cain told CNN.
“Debris started raining down, which you know, sort of looked like it was floating down and not very heavy, but actually now looking at it, it’s giant metal pieces all over the place,” he said.
“I was surprised that the plane sort of continued on uninterrupted, without really altering its trajectory or doing anything,” he said. “It just kind of kept going the way it was going as if nothing happened.”
Cain said he and his children took shelter at a gazebo near the playground and watched the debris come down about two or three blocks away.
“So then I went upstairs to get my wife and baby who were napping upstairs and have them come down and make sure they were safe,” he said.
CNN’s Hollie Silverman contributed to this report.