WASHINGTON – Like a lot of air travelers this holiday season, Eileen Dunn said she’s sick of buying a ticket, then getting hit with a variety of fees.

“I am a senior citizen and cannot afford the extra, unknown beforehand expenses imposed on me,” Dunn wrote in one of hundreds of letters and messages sent to the U.S. Department of Transportation seeking it to force airlines to more visibly disclose fees tacked onto their fares.

In October, about three weeks before the presidential election, transportation officials said they were considering such a rule. They also said they could enact rules making it easier for travelers to shop online for the cheapest fares.

But prospects of those new rules are now in doubt, illustrating a tension between President-elect Donald Trump’s populist rhetoric and his promises to ease regulations on industry.

“If (transportation officials) don’t do it soon, it doesn’t look like it’s going to happen,” said Paul Hudson, president of FlyersRights.org, an airline travelers advocacy group.

“On Jan. 20, it’s going back to the drawing board,” he said, referring to Trump’s inauguration, though Trump has yet to take a formal position.

The airline industry opposes the regulations, including one requiring air carriers and online sites such as Orbitz and Kayak to display fees for baggage and other extras alongside fares.

“What customers want to know is, ‘How much do I have to pay for this trip?’” Hudson said.

Unless all the fees are visible next to a fare, he said, “Comparison shopping becomes like a research project.” What might look like the cheapest fare might not be when all the fees are factored in.

Airlines have begun to restrict online travel sites from showing their flights. The Transportation Department is seeking comments about whether to force airlines to make schedules and fares available.

The industry calls both potential rules overly aggressive, warning that they could increase fares and make searching for flights a lot slower.

A separate regulation, announced in October, is likely to continue. It requires airlines to refund fees for checked baggage if there is a delay in delivering passengers’ bags.

Unlike the other rules, Congress mandated refunds on baggage fees in a bipartisan bill passed in July.

The other regulations, however, are more controversial.

At issue is growing frustration over fees estimated to have raised $31.5 billion in 2013.

“Baggage-fee information is often buried on a carrier’s website and can be confusing and complex,” the passengers’ group wrote to the Transportation Department.

Greater disclosure, it said, is all the more important as passengers face more fees beyond listed fares.

“Seat assignment availability is being manipulated to falsely show very few-to-no seats available in order to get consumers to pay extra increased fees,” the group noted.

Elderly and disabled passengers, as well as families with small children, are also pressured to pay for priority boarding.

Fees to change flights can be as high as $200 domestically and $500 for international flights, said the group, calling the charges “clearly exorbitant, unfair and unreasonable.”

Consumers Union and the Public Interest Research Group have also called for more regulations.

However, the industry group Airlines for America argues that listing all fees alongside online fares is untenable.

It would force shoppers to spend 20 to 40 more seconds sifting through “redundant or conflicting information about pricing of ancillaries,” it wrote in a letter to the Transportation Department.

Hudson said the ability to shop around is also limited by airlines refusing to be listed on travel websites. Airlines want shoppers to buy tickets from their own sites, where they offer options for extra services, such as seat selection or printing out a boarding pass at the airport.

Southwest Airlines also does not allow search sites to show its fares, and Delta Air Lines only allows some to list its flights.

Airlines also don’t want shoppers to go to websites to comparison shop, said Emily Cullum, spokeswoman for the Travel Tech Association, which represents travel websites.

Travel Tech estimated in a study that shoppers could pay $30 more per ticket, or a total of $6.7 billion annually, if more airlines refuse to be listed on travel sites.

“Given the unprecedented level of consolidation in the airline industry, it is more important than ever that Americans maintain the ability to comparison shop,” wrote Sens. Elizabeth Warren, D-Mass., and Richard Blumenthal, D-Conn., in a letter to the Transportation Department supporting a rule.

But for airlines, the government has no business dictating whom they do business with.

Delta spokeswoman Elizabeth Wolf said it chooses to not appear on websites it considers to have “misleading, deceptive and/or fraudulent business practices.”

She also said that if even fees are not available at the outset, customers have a chance to review them before buying tickets.

Southwest Airlines spokesman Dan Landson said selling tickets only through its own website “means there’s no middleman … thus keeping costs low and passing the savings on to travelers.”

The government regulating how it sells tickets would be “unprecedented,” he said. Landson said it would lead shoppers to sites that aren’t as “easy-to-use, transparent and consumer friendly” as the airline’s own site.

Kery Murakami is the Washington, D.C. reporter for CNHI’s newspapers and websites. Contact him at kmurakami@cnhi.com.