The Transportation Department said it is directing Southwest to provide substantive responses to all consumer complaints within 60 days, as required by federal regulations.

ENFORCING REIMBURSEMENTS

The agency has repeatedly vowed to hold Southwest accountable if it fails to adhere to the promises made to reimburse passengers affected by the more than 16,000 flights canceled due to a severe winter storm and the company's dated technology.

Southwest said on Tuesday it is "making every effort" to refund and reimburse customers, and is now processing flight refund requests within an average of about three days.

"We appreciate our customers' patience as we continue this all-hands effort to assist those affected by the recent travel disruption," the company said in a statement.

Southwest on Tuesday also launched a seasonal sale for fares as low as $49 for some one-way routes. Southwest offered a similar sale last January, with fares as low as $39 one-way.

Some analysts were expecting the fare sale as part of the airline's efforts to mollify customers and deflect attention away from the recent meltdown.

Southwest is under pressure from some investors to win over customers after it warned it would take a quarterly profit hit of as much as $825 million.

REROUTED RIBEYE

Some Southwest customers remain upset.

Connie Henderson, 56, of Stockton, California, had scheduled to fly to Houston, through Las Vegas, to spend Christmas with her extended family, and was traveling with a cooler filled with a $70 ribeye roast to feed everyone.

After her first flight was delayed three times, the property manager rebooked for the next day, but the cooler was already en route to one location and her suitcase to another, she said. It took her three trips to the airport, over 10 hours in line, and a week of waiting to get both items returned, and the cooler was empty after she warned the airline the food would spoil.

Henderson said she received two $300 vouchers for the misplaced luggage, travel points worth $300 and another 28,000 points, but still intends to ask for money to cover the extra driving, parking and other costs related to the experience.

"We were going to have Christmas dinner," she said. "I try not to cry, but I was so heartbroken."