US court upholds rules showing plane tickets' real cost

WASHINGTON (Reuters) - U.S. regulators acted within their authority when they imposed new airline ticketing rules, such as requiring that the total price including taxes be prominently displayed in print advertisements, a federal appeals court ruled on Tuesday.

The ruling is a defeat for Allegiant Travel Co (ALGT.O), Southwest Airlines Co (LUV.N) and Spirit Airlines Inc (SAVE.O), which challenged all or some of the rules.

Evidence submitted "sufficiently support the intuitive conclusion that customers are likely to be deceived by price quotes significantly lower than the actual cost of travel," Judge David Tatel of the U.S. Court of Appeals for the District of Columbia Circuit wrote.

In morning trade, Allegiant was down about 1 percent, Southwest down about 0.5 percent and Spirit up about 1.2 percent. U.S. markets were lower overall.

(Reporting by David Ingram; Editing by Gerald E. McCormick and Leslie Gevirtz)