AirTran Airways and Delta Air Lines on Sunday resumed their service into St. Louis, where tornado damage had caused flight cancellations this weekend.

The concourse used by AirTran at Lambert Airport was the most severely damaged Friday night and is likely going to be out of operation for some time, AirTran spokeswoman Judy Graham-Weaver said. For that reason, AirTran is shifting its operations to another concourse at the airport, she said.

"We've been working all night on it," Graham-Weaver said. "We're getting back up and running."

AirTran operates 11 flights a day into St. Louis. Four of those flights were canceled Sunday, but the rest will make the trip, she said.

Although AirTran's concourse -- Concourse C -- was the hardest hit by the tornado, Graham-Weaver said, none of the airline’s aircraft sustained any damage and all of its personnel had been accounted for.

“Everybody is fine,” she said.

On Sunday, AirTran will begin using Concourse B.

Delta also resumed flights into St. Louis on Sunday, airline spokesman Paul Skrbec said.

"We expect to run a standard operation today," he said.

For additional flight information, passengers can check  AirTran.com or Delta.com.

According to an Associated Press report, St. Louis Mayor Francis Slay said the airport could be operating at 70 percent capacity starting Sunday. Complete repairs could take two months.