More than 3000 suitcases were left piled on the tarmac at Phoenix airport after the baggage-screening systems failed.
Workers at Phoenix Sky Harbor International Airport were forced to search hundreds of items of baggage by hand or load them on to trailers on Thursday evening to be taken by ground to airports in Tucson and San Diego so they could be screened and flown on to passenger destinations.
The computer systems were apparently fixed on Thursday and were be testing through the night ahead of scheduled flights on Friday, Transportation Security Administration (TSA) spokesman Nico Melendez said.
He added: "We are cautiously optimistic that it will be fully operational in the morning."
Additional sniffer dogs and specialists were being brought in from other airports in case of further problems on Friday.
Julie Rodriguez, a spokeswoman for Sky Harbor, said the problem hit all three of the airport's terminals.
According to the TSA, the inline baggage systems handle the majority of luggage checked in at airports. When everything is working properly, only about 10% of all checked baggage is hand-searched by TSA officers.
Nearly 4.3 million passengers travelled through Sky Harbor airport in March.