Hundreds of Northwest Airlines passengers had to wait for ticket agents to check them in manually Tuesday because of a computer problem that delayed some flights and canceled others.
The problem, which developed about 1:30 p.m. Tuesday, affected some Northwest and Northwest Airlink flights in the United States and Canada.
Northwest spokesman Kurt Ebenhoch said Detroit Metropolitan Airport was the most seriously affected of the airline's three U.S. hubs. Minneapolis-St. Paul and Memphis were experiencing fewer delays.
A few Airlink flights, operated by Pinnacle Airlines and Mesaba Airlines, were canceled, he said.
The computer system gradually began returning to normal at 2:15 p.m. but was still operating at limited capacity late Tuesday evening, Ebenhoch said.
Northwest was using other systems and manual backup plans to minimize the impact of the problem, he said.
The company also issued a waiver allowing customers to change their travel plans without penalty. Customers with confirmed tickets to fly Tuesday and Wednesday may reschedule their travel to begin no later than Aug. 1 without penalty or administrative fees.