The Biden administration proposed a rule on Thursday that would prevent airlines from charging extra for families with young children to sit near each other in a push to crack down on so-called junk fees.

The rule is the administration’s third this year focused on passenger protection, adding to one seeking price transparency and another requiring quick refunds on canceled flights.

“This is, of course, part of the bigger picture of the Biden-Harris administration’s work to protect the rights of consumers, including airline passengers,” Transportation Secretary Pete Buttigieg said on a call with reporters. “Families don’t need any additional stresses or costs when flying on top of how demanding it can be to be a parent flying with your kids.”

The proposed rule would require airlines to seat parents next to their young children, defined as 13 and under, for free within 48 hours of booking. That means adjacent or in the same row, but not separated by an aisle, in every class of service. Airlines would be prohibited from defining class in a way that limits availability of family seating.

In situations where it is impossible to provide adjacent seating for multiple young children, it would require seats across the aisle from, directly in front of, or directly behind the parent or accompanying adult.

If adjacent family seats are not available at booking, airlines would be required to provide passengers the choice between receiving a full refund or waiting for family seating to become available later. If they choose to wait and adjacent seats do not free up, airlines must give families an option to rebook for free on the next flight with available family seating.

Airlines would also have to disclose “clearly and conspicuously” that family seating is free. Airlines that violate the rule would be subject to civil penalties for each violation.

White House officials said on a call with reporters that the fee-free family seating rule would save a family of four as much as $200 per round trip if seat fees are $25. Buttigieg added that it would also avoid situations where passengers are asked to give up their seat for a family to sit together.

The notion of fee-free family seating has been popular among lawmakers in Congress. Lawmakers included a provision directing the Federal Aviation Administration to propose a rule banning such fees in an FAA reauthorization bill passed earlier this year.

Airlines for America, which has opposed many Biden administration airlines rules, has argued that many airlines already provide family seating free of charge.

According to DOT’s Airline Customer Service Dashboard, Delta Air Lines, Southwest Airlines, Spirit Airlines and United Airlines are among the larger air carriers that have not committed to fee-free family seating.

The proposed rule comes just a few days after the 5th U.S. Circuit Court of Appeals sided with airlines and blocked a previous Biden administration rule requiring airlines to disclose extra service fees. In a decision filed Monday, the court said the rule likely exceeds DOT authority and will “irreparably harm” airlines.

“The airline industry lobby is trying to tie this up with lawsuits, but we will not back down from protecting passengers,” Buttigieg wrote on X after the ruling. “Airlines are simply wrong to argue that merely having to disclose their fees would ‘irreparably harm’ them. It’s common sense.”