SEATTLE >> Airlines and online ticket sellers began complying today with a new federal rule requiring them to include taxes and fees in advertised fares.

Alaska Airlines now shows the full fares, including taxes and fees, in its low-fare calendars and searches by schedule and price. Customers can see what the fare would be without taxes and fees by placing their mouse over the fare they select.

The price of a one-way ticket between Seattle and Honolulu on Feb. 1, for instance, shows up on the airline’s low-fare calendar as $272. Click to select the fare and you also see $242, the price without taxes and fees. Once you select the fare, the $242 price comes up on the left of the screen in light type, followed by a break out of $30 in taxes and fees and the final price of $272 in bold.

No longer acceptable is listing prices, not including taxes and fees, in big, bold type, followed by the bottom-line price in small print.

“Under the new rules, they will have to incorporate taxes and fees into the fare that’s stated — the first fare that the customer sees,” U.S. Department of Transportation spokesman Bill Mosley said in an interview a few weeks ago.

Other airlines seemed to be complying. Delta Air Lines, which used to show prices without taxes and fees in big, bold type, followed by the inclusive price in fine print, now shows the total price, including taxes and fees, in bold print.

Online ticket sellers Expedia and Travelocity are also now displaying inclusive prices. Expedia turned the new rule into a marketing opportunity with an orange banner advertisement on its search page, pointing out that “Now it’s easier to find the best fare. Taxes and fees are now included in the total price.”

Orbitz was displaying fares, without taxes and fees in orange type, followed by the total price in black type. Search results for a round-trip fare between Seattle and Boston in February, for example, brought up a low fare display as “$396 + $39 in taxes and fees” for a total of $435.

The Business Travel Coalition denounced Spirit Airlines for misleading customers by placing a red “warning” sign on its website saying “new government regulations require us to HIDE taxes in your fares.”

“The plain truth is that airlines are allowed to break out these tax items on their websites and in print advertising in as much detail as they care to so long as the breakout is not more prominent than the total price — to avoid misleading consumers,” the business group said in a statement.

Spirit Airlines and Allegiant Air have challenged the new rules in court.

“If the government can hide taxes in your airfares, then they can carry out their hidden agenda and quietly increase their taxes,” Spirit warned on its website.

Sen. Barbara Boxer called the warning 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.”