The US Customs and Border Protection processing systems were back online at all airports later in the night, spokesman Daniel Hetlage said -- but not before creating long lines of disgruntled holiday travelers.
The outage lasted from about 5 to 9 p.m. ET, Hetlage said. Airport officials and travelers across the country reported delays ranging from 30 minutes to two hours.
CBP officers processed international travelers through "alternative procedures" while the agency scrambled to get systems back online.
"During the technology disruption, CBP had access to national security-related databases and all travelers were screened according to security standards," Hetlage said. "At this time, there is no indication the service disruption was malicious in nature."
The outage affected passengers on more than 30 flights into Miami International Airport beginning at 6 p.m., spokeswoman Suzy Trutie said. Even after service resumed, the airport said it would take extra time for CBP officers to process.
The outage lasted about 90 minutes at Hartsfield-Jackson Atlanta International Airport before computers were running again, US Customs and Border Protection spokesman Rob Brisley said.
Jennifer Powers-Johnson was returning from a family vacation in London when she arrived at Salt Lake City International Airport.
"Delta had us all line up after we landed and it took a while before customs was even able to find us a place where we could wait because the airport is so small," Powers-Johnson said. "I would not have had any idea of what was going on if my cousin did not text me."
College student Chinedu Elendu was returning with his brother and sister from a family vacation in Nigeria when the outage held him up for about an hour and a half at San Francisco International Airport.
They had just finished two legs of their journey: a 6.5-hour flight from Nigeria to Frankfurt, Germany, followed by an 11.5-hour flight to San Francisco, he said.
"When we got to the place in customs where you scan your passport, my brother and sister scanned theirs and got through fine. Mine did not scan and I had to get in a different line. That was the line that took so long," Elendu said.
No announcements were made at the airport explaining the delay, he said. He overheard people talking about a nationwide computer problem affecting people with all kinds of passports.
Elendu still had one more leg of his trip as he headed back to Portland, Oregon, for school.