The FAA has said it expects the national air travel system to return to normal by Sunday. But as of Saturday, airlines were still working to reposition aircraft and crews, leaving passengers stranded or uncertain about whether their flights would leave at all.

At JAX, the mood ranged from relief to exhaustion. Marria Kok, trying to get her family home to Idaho, said the past 24 hours had been a roller coaster.

"We were just hoping it all worked out and everything got fixed," Kok said. "And they said it did, but obviously not too much, because we're stuck here."

Kok's family had finished a vacation in Orlando when their flight home was canceled Friday. Hoping to improve their odds, they paid $300 for an Uber to Jacksonville late Friday night. Their Saturday flight was then delayed, forcing them to spend another night in the terminal.

"So here we are just camping out in the airport, hopefully only for tonight," she said. Her children, she added, have been passing the time on their phones. "Hopefully we can get home and get to our normal life routine again because they've already missed a week of school."

The family was hoping to catch a 6 a.m. flight Sunday, though airline officials could not guarantee it would depart.

Others faced similar uncertainty. Seth Warren spent the day searching for his father, who was traveling from Ecuador.

"His phone doesn't work in America," Warren said. "So I've just been coming back and forth. I've been trying to find him because they won't give me any information up front."

Paul Alva, headed to Atlanta, managed to rebook after his original flight was canceled.

"Didn't know if I was going to get a flight today, but I was lucky to get one," Alva said. "As soon as it was canceled, I booked the next flight and it was available. Now I'm just waiting, hopefully they don't cancel this flight."

Kyle Jackson, traveling to Los Angeles, worried about connecting flights and a long night ahead.

"Just kind of worried that there's a domino effect and if there's any connecting flights, those may be impacted," Jackson said. "It might be a long night in the airports."

One passenger bound for Philadelphia said simply: "No updates, just got straight canceled."

Jarron Mike, trying to reach Atlanta, said the scale of the disruption caught him off guard. "I never seen something like that before, so I was just kind of blown away," he said.

Despite the chaos, some travelers tried to keep perspective. "Don't let this one day hinder your travels," said one man waiting for his wife to return from Atlanta.

Jackson had a pragmatic take: "So I guess all you do is go find a restaurant, get a beer and a plate of food and wait it out."

The FAA has not detailed what caused the ground stop, which halted flights across the country. Homeland Security officials sought to reassure the public, saying the outage was "not another 9/11" and that everyone was safe. The National Weather Service also pushed back on rumors of a radar outage, setting the record straight.

For now, travelers at JAX are advised to check with their airlines before heading to the airport, as schedules continue to shift.