(CNN)Travelers flying out of Phoenix Thursday are no doubt safely at their destinations by now.
For their luggage -- much different story.
After a screening glitch that lasted hours Thursday, travelers by the hundreds were left wondering when their belongings would show up.
Thousands of checked bags piled up at Sky Harbor Airport in Phoenix after technical issues with computer servers prevented the Transportation Security Administration from using machines to screen the luggage.
As a result, more than 3,000 bags missed flights, said spokesman Nico Melendez of the TSA.
The baggage screening resumed late Thursday night and the systems were operational, CNN affiliate KPHO reported.
By mid-day Friday, things were "back to normal," according to Southwest Airlines spokesman Chris Mainz.
"We are working as quickly as we can to reunite bags with customers today," Mainz said. "We should recover fully today."
Many of the backlogged bags were stacked up in a parking lot Thursday while their owners went on to their destinations.
Before screening resumed, there were a lot of grumpy people at the airport.
"It's frustrating, yes. I'm tired, tired as everybody else," one passenger told CNN affiliate KNXV. "I thought if this had happened before maybe there would be a better system in place."
Traveler Mindy McLarren told CNN affiliate KPHO that some bags were being checked by hand.
"It's very stressful because I hope that everything that I packed is still in there after people have hand-checked it. And just that it gets there on time," she said.
McLarren said she took things out of a bag to be checked and put them in her carry-on.
Before it was resolved Thursday night, the problem had gone on for hours, since 6:45 that morning, the TSA said.
Officers switched to an alternative system and brought in additional bomb-sniffing dogs as the bags kept coming. Later in the day, officials brought in tractor-trailers to take some of the bags to other airports.