MILWAUKEE (CBS 58) -- More than 15,000 U.S. flights were canceled Friday after the Federal Aviation Administration issued a nationwide ground stop.

That was lifted hours later, however thousands of flights Saturday are still expected to be canceled or delayed.

Travelers at Milwaukee's Mitchell International Airport who spoke to CBS 58 said they just wanted to get home.

Paul Donelson was in town for what was supposed to be a quick work trip -- but multiple flights back to Houston ended up getting canceled.

"Quite a journey but it could be worse," Donelson said. "It's out of your control so you just control the things you can and make the best of it... but I'm ready to get home to 67-degree weather rather than the 33-degree weather."

Becky Dix was in town from Dallas taking care of her elderly father.

"I feel bad for the people, there's a man who can't get to Tampa and his son is having brain surgery," Dix recalled. "My flight is just delayed, it's a turnaround flight, it's leaving Dallas, it said it's boarding so I have a plane so I'm heading back to Dallas, but I love Wisconsin so I would be okay if I stayed."

Tino Merazze from Germany said when his flight was canceled, he rushed to book a hotel room only to find out when he arrived and had already paid that the hotel was full.

Thankfully, he got a refund and was able to find another room at a second hotel.

"They check me in again for another plane, it cancels again, I run to another gate and cancelled again and then they told me tomorrow morning at 4 o'clock, I come here at 4:30, cancelled," Merazze said. "I think they did everything they can so it's good for safety, I don't know what happened, I think it was a software problem."

Secretary of Transportation Sean Duffy blamed old air traffic control technology and overloaded routers.

Markwayne Mullins, the secretary for Homeland Security, added this did not stem from a threat to the U.S., and it is not linked to this week's Microsoft outage.