American Airlines played catch-up Wednesday, resuming most flights and even adding a handful that were not on the schedule to help passengers stranded by a massive technology failure that grounded the carrier's entire U.S. fleet.
A day after the nationwide breakdown, some cancellations persisted, and delays were still common. About a third of American flights were late as of mid-afternoon.
American's CEO blamed Tuesday's failure on a software problem that knocked out computers needed for booking flights, tracking bags, loading and fueling planes and more.
"As you'd imagine, we do have redundancies in our system," Tom Horton, chief executive of parent company AMR Corp., said in an apology posted on YouTube. "But unfortunately in this case, we had a software issue that impacted both our primary and backup systems."
American and smaller-jet subsidiary American Eagle canceled more than 300 flights by mid-afternoon, according to flight-tracking service FlightAware.com. American said some flights were affected by bad weather in Chicago.
But the airline's performance was a huge improvement over Tuesday, when the computer trouble brought all departures to a halt. Flights already in the air were allowed to continue to their destinations, but planes on the ground could not take off.
American and American Eagle canceled nearly 1,000 flights and delayed another 1,100. Two-thirds of their scheduled flights were late or never got into the air.
On Wednesday, American added seven unscheduled flights to accommodate passengers stranded the day before in Chicago, Dallas and Los Angeles.
As marooned passengers resume their travels, questions lingered about the technology and whether American's systems will be adequate to avoid similar collapses after the company merges with US Airways to form the world's biggest airline.
Money has been tight for airlines in recent years, so spending has been focused on immediate needs rather than upgrading technology, said Ira Gershkoff, who runs SlipStream Aviation Software and has worked as a technology executive for Polar Air Cargo, travel technology company Sabre Inc. and at American Airlines.