Low-fare carrier Spirit Airlines continued its public criticism of new U.S. Department of Transportation (DOT) passenger-protection rules, drawing a rebuke from a U.S. senator. The airline also faced a new fine from the DOT over its handling of complaints lodged by passengers with disabilities.

Spirit announced January 31 that it will introduce a $2 “DOTUC” fee to cover the “unintended consequences” of the new government regulations. It specifically cited a requirement that airlines hold reservations at the quoted fare without payment for at least 24 hours after the reservation gets made, as long the customer reserves the ticket one week before the departure date. “This rule mandates that we take out seat inventory for those who may or may not decide to pay for it,” Spirit said. “This prevents us from selling these seats to someone who definitively wants to book a reservation and leads to seats not being filled. The consequence is that we must spread costs over fewer customers, thus raising the cost for all passengers.”

The Miramar, Fla.-based carrier is contesting aspects of the DOT passenger-protection rule in the U.S. Court of Appeals for the D.C. Circuit, as are Allegiant Air and Southwest Airlines. The DOT issued the rule last April. Some provisions took effect over the summer; provisions relating to reservations, advertising and other matters went into effect last month.

A January 24 missive from Spirit drew a response from Sen. Barbara Boxer, a California Democrat who sits on the Senate Transportation Committee, Aviation Operations subcommittee. In a press release, Spirit charged that the DOT is requiring airlines to hide the cost of government taxes and fees by lumping them together with the airline’s charge under the so-called “full-fare advertising” rule. Spirit said it is mounting a public awareness campaign with a web site, keepmyfareslow.org, that enables visitors to contact members of Congress.

Boxer issued a press release January 26, calling on Spirit CEO Ben Baldanza “to end the airline’s deliberate attempt to deceive the flying public” about the effects of the DOT regulation. “What the rule says is that you have to tell your customers the full cost of a ticket,” Boxer wrote in a letter to Baldanza. “And despite Spirit’s claim that the airline must now hide relevant information, the rule ‘allows carriers to advise the public in their fare solicitations about government taxes and fees.’”

The DOT announced on January 27 that it has fined Spirit $100,000 for failing to properly record and respond to complaints from passengers with disabilities. In November, the department fined Spirit $50,000 for violating existing price advertising rules.