The US Department of Transportation (DOT) has assessed a $150,000 civil penalty against Southwest Airlines for not responding in a “timely manner” to complaints filed by consumers. The airline is also alleged to have not adequately responded to the passengers’ specific complaints in its responses. The DOT ordered the airline to cease and desist from further violations. It says a large number of disability-related and other consumer complaints from June 2011 until January 2012 were involved in the action. Some of the complaints related to a problem with Southwest’s website during this time.