In the last year or so, the U.S. Dept of Transportation has instituted a number of new rules — like requiring airlines to include all known taxes and fees in its advertised prices — aimed at adding more transparency to airfares. Some carriers, especially discount airlines that love to advertise a bottom-dollar price with oodles of fine print hiding the fact that it’s not such a good price, have challenged these changes. But today, a U.S. appeals court sided with federal regulators (and common sense).

The rules had been challenged by the troika of Southwest Airlines, Spirit Airlines and Allegiant Travel.

But the judge for the D.C.-based U.S. Court of Appeals said that the evidence in the case “sufficiently support the intuitive conclusion that customers are likely to be deceived by price quotes significantly lower than the actual cost of travel.”

Back in February, Allegiant was slapped with a $100,000 fine after advertising that passengers could “fly free” to Las Vegas, even though customers still had to pay fees and taxes.

Meanwhile, Spirit Airlines was sued by the Dept. of Transportation when it decided to slap on a $2 “Unintended Consequences Fee” in response to a DOT rule change that requires airlines to allow passengers to change flights without penalty within the first 24 hours of booking.

Spirit was also publicly taken to task by Senator Barbara Boxer after the airline e-mailed its customers to say that these new fare transparency rules were actually a ruse by the federal government to hide new taxes and fees.

US court upholds rules showing plane tickets’ real cost [Reuters]

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