PHILADELPHIA – Sweeping pro-consumer passenger rights rules go into effect Aug. 23 that require airlines to refund baggage fees for lost checked luggage and to pay more for involuntarily bumping passengers on over-booked flights.

The rules, designed to protect airline consumers from unfair and deceptive practices, extend fines to foreign carriers and to international flights by U.S. airlines, if passengers are stuck on airport tarmacs for more than four hours.

The new requirements have been praised by passenger rights advocates, but criticized by the airline industry for adding costs and challenges that could lead to higher ticket prices and more cancellations.

Spirit Airlines Inc. and Allegiant Air, joined by Southwest Airlines Co., are challenging one or more of the provisions, including a requirement that advertised fares include all government taxes and fees.

Airlines previously could list taxes and some passenger fees separately from an advertised fare, as long as they were prominently footnoted or linked.

The U.S Transportation Department filed a rebuttal with the U.S. Court of Appeals in Washington on Aug. 4, defending the full-fare advertising rule to help the public ascertain the true cost of air travel.

“The new rules have gone further than any such protections in the history of U.S. commercial aviation,” said Kevin Mitchell, chairman of the Business Travel Coalition in Radnor, Pa.

Airlines were successful in delaying until Jan. 24 implementation of some measures, such as prompt notification of flight delays and cancellations; allowing passengers to cancel a reservation, without penalty, within 24 hours; and publishing full fares in advertising.

Starting Aug. 23, airlines must disclose on their websites all optional or “ancillary” charges. This will be a “link” to a page listing all the fees, said Kate Hanni, executive director of FlyersRights.org. “It’s not exactly what we had hoped for. It’s not going to give you the ability to compare apples to apples amongst other carriers. We are still fighting for that.”

The Transportation Department is contemplating an additional rule that would force airlines to provide their “ancillary” fee information to travel agents and online ticket distribution systems, such as Expedia and Travelocity, so that consumers can compare the fee-inclusive fares of various airlines.

“There are a zillion fees,” said Mitchell.