01/26/2012 01:04 pm ET Updated Mar 27, 2012

Senator Barbara Boxer Slams Spirit Airlines' 'Deliberate Attempt To Deceive' Fliers

In a letter today to the CEO of low cost carrier Spirit Airlines, Senator Barbara Boxer (D-CA) says the airline is engaged in a "deliberate attempt to deceive the flying public about a new Department of Transportation (DOT) rule that will improve the transparency of airfares for consumers."

The rule, which comes into effect today, requires airlines to include mandatory government taxes, fees and other charges in advertisements of airfares.

Spirit, which is known for its alluring come-on fares often advertised for as little as $9, recently sent an email to customers saying: "New government regulations require us to HIDE taxes in your fares.” The same line still appeared in a splash graphic on the airline's website as of noon Thursday.

"Nothing could be further from the truth," Boxer writes in her letter. "What the rule says is that you have to tell your customers the full cost of a ticket. It prohibits Spirit or any other airline from advertising fares 'that exclude taxes, fees or other charges since the major impact of such presentations is to confuse and deceive consumers.'"

Boxer's view is supported by independent industry watchers. In an interview with HuffPost Travel last week, Travelzoo's US Web Editor Andrew Young described the new rules as "good for the consumer." Founder of Airfarewatchdog and HuffPost Travel blogger George Hobica writes that "If you're an airline, January 26, 2012 is a day that will go down in infamy."

On New York's WPIX Thursday morning, consumer advocate Christopher Elliott said the changes are a win for fliers.

"Before the rules took effect, you really didn't know how much you were paying for your airline ticket until you got to the very end of the booking," Elliott told the network.

In her letter, Boxer urges Spirit CEO Ben Baldanza to send an email to customers clarifying its comments.

Misty Pinson, director of corporate communications for Spirit says the airline was "disappointed" by the letter.

"We have always shown taxes before someone purchased," Pinson writes in an email to HuffPost Travel. "We would welcome the opportunity to sit down with [Boxer] and discuss the facts so she is fully informed."