ATLANTA (AP) -- Delta Air Lines said Friday it has canceled about 3,000 flights this week as it struggles in the aftermath of a storm that hit its big hub airport in Atlanta.
The thunder storm hit Wednesday, but canceled flights and long lines in Atlanta persisted into Friday. Delta had canceled more than 400 flights by midday Friday, according to tracking service FlightAware.com.
The airline said it is still getting planes and crews back in position for flights. Atlanta is Delta's busiest airport, and about 60 percent of its planes go through Atlanta on an average day.
Wednesday's storm was "unprecedented" and hard to forecast, said the airline's chief operating officer, Gil West. He added, "we understand the resulting recovery has not been ideal and we apologize for that."
On Twitter, Delta told people who were expecting to fly Friday to check their flight's status before going to the airport.
Delta was having trouble rebooking passengers because there weren't many empty seats on later flights. In March, the average Delta flight was about 85 percent full.
Most leading U.S. airlines have tried to limit empty seats by reducing the growth of flights. That has helped boost the airlines' profits but makes it harder to rebook passengers when flights are canceled.
Delta travelers whose flights are canceled can get a refund. The airline also offered to waive change fees for those who rebooked their plans.
The 3,000 cancelations, which included Delta and Delta Connection flights, topped the 2,300 that were canceled last August after a fire and power outage at a Delta data center in Atlanta. That airline later estimated that breakdown, which lasted four days, cost it $150 million.