The failure has caused delays at the Seattle-based airline's entire network of 64 destinations, which also includes airports in Alaska, Mexico and Canada. Alaska Airlines has an average of 436 flights a day.
Airline spokeswoman Marianne Lindsey says technicians are trying to restore the reservation network that was lost at 7:40 a.m. Monday.
The airline says the problem was caused when a Sprint fiber optic network in the Midwest was cut and Alaska Airlines lost its connection to the Sabre ticketing system.
The airline had hoped for a partial solution by noon Pacific time, but there was no indication a fix was imminent.