Southwest Airlines, the nation's largest domestic carrier, agreed to pay a $150,000 fine for failing to give timely responses to passenger complaints.
The U.S. Department of Transportation announced the fine Wednesday, saying Southwest did not respond in writing within 30 days to complaints related to access for the disabled, as required by federal regulations.
Southwest officials said the airline inadvertently missed the complaints because of a technical glitch.
The Department of Transportation said the airline didn't learn of the problem until seven months after it began.
Once Southwest discovered the problem, airline officials did not address the facts of each complaint but simply provided the airline's policy on disability-related issues, according to the federal agency.
Still, the Department of Transportation gave the airline a credit of $115,000 toward the fine because Southwest spent $115,000 to refund the tickets of the customers who filed the complaints.