I remember years ago, I think it was in California while I was stationed down there, that they tried to pass a law that would have prohibited gas stations from posting the cost of taxes in a gallon of a gas. I also remember another case where there was an effort to require "total cost" pricing in retail stores, which would have had the effect of masking the amount of taxes you were paying on any purchases you made.
The Department of Transportation is making the same move on airlines, prohibiting them from emphasizing the cost of taxes and fees on your airline ticket. Several airlines, including Spirit, Allegiant, and Southwest, filed suit against the DOT. They wish to emphasize to their customers exactly how much the government is increasing the cost of an airline ticket. The U.S. Court of Appeals for the DC circuit found against them.
Hopefully the Supreme Court will take this up and overturn the ruling. If you can't publicize government policies that you disagree with, what is the point of the First Amendment?