Travelers wait in line at the Delta check-in counter at LaGuardia Airport (Drew Angerer/Getty Images)

NEWARK — Delta is back in the air Tuesday after Monday's computer issues, but several hundred flights have already been canceled nationwide as the airline is works to "reset" its operations.

In a statement on its website, the airline said it is working to get crews, aircraft and "other operational elements" in place. As of 6 a.m., 250 flights had been canceled for Tuesday. The website flightstats.com showed 5 flights leaving Newark on Tuesday morning and two flights headed into Newark as being canceled.

"We were able to bring our systems back on line and resume flights within a few hours yesterday but we are still operating in recovery mode,” Dave Holtz, senior vice president of operations, said in a statement on the Delta Airlines website. “We are sorry for what many of our customers have experienced over the past 24 hours, including those who remain at airports and continue waiting for their flights. We are doing everything we can to return our operation to normal reliability, but we do expect additional delays and cancellations.”

Delta was extending its travel waiver to customers flying Tuesday, allowing a one-time change to a ticket without a fee. Passengers who had delays of three hours or longer will also receive $200 in travel vouchers.

Over 1,000 flights were canceled on Monday because of a loss of power in Atlanta  the airline said affected its system worldwide and completely grounding its flights for several hours.

A spokesman for Georgia Power said that the company believes a failure of Delta equipment caused the airline's power outage. He said no other customers lost power. Delta declined to comment on the power company's report.

The Associated Press contributed to this report