CHICAGO (NewsNation) — Several U.S. airlines are suing the Transportation Department over a rule requiring greater transparency for disclosing so-called “hidden junk fees” to customers while shopping for flights.

The airlines asked a federal appeals court to block the rule, which the DOT announced on April 24. The rule requires better disclosure of fees on baggage and changing or canceling a reservation.

Airlines argue that the rule will confuse consumers by giving them too much information during the ticket-buying process. However, the Biden administration asserts the average customer overpays more than $500 in extra fees every year.

The DOT said Monday it will defend the rule to crack down on what it calls “hidden junk fees.”

What is the new rules’ requirements?

The DOT’s new rule would require airlines and travel agents to disclose upfront any charges for baggage and canceling or changing a reservation.

Airlines must show the fees on the first website page where they quote a price for a flight.

The agency estimated that the rule will save consumers more than $500 million per year.

“We will vigorously defend our rule protecting people from hidden junk fees and ensuring travelers can see the full price of a flight before they purchase a ticket,” the DOT said.

Airlines argue the new rule is unnecessary

American, Delta, United and three other carriers, along with their industry trade group Airlines for America, filed a class action lawsuit in the 5th U.S. Circuit Court of Appeals in New Orleans Friday.

Airlines for America said the DOT is going beyond its authority by attempting “to regulate private business operations in a thriving marketplace.” The airlines claim they currently supply customers with a complete list of fees before booking their flights and the new rules are unnecessary.

“The ancillary fee rule by the Department of Transportation will greatly confuse consumers who will be inundated with information that will only serve to complicate the buying process,” Airlines for America said.

Customers ‘frustrated’ with junk fees

As far as new rules about refunds are concerned, some customers say they’ll appreciate greater transparency.

“Scrambled to find other airlines’ flights to get on and then have to pay for that and not get refunded because you chose not to take that flight. So, yeah, it’s been frustrating,” a traveler told NewsNation.

Southwest Airlines was the only carrier among the nation’s six biggest airlines that did not join the lawsuit as the rule does not affect them. The airline allows passengers to check two bags for free and has never charged extra fees for changing or canceling reservations.

The Associated Press contributed to this report.