The U.S. Department of Transportation (USDOT) announced on Monday that three American airlines have agreed to express their commitment in writing to do away with family seating costs if adjacent seats are available upon booking.

American Airlines (AAL.O), Alaska Airlines (ALK.N), and Frontier Airlines (ULCC.O) will all incorporate the guarantee in their customer service programs as a result of pressure from the Biden administration.

Transportation Secretary Pete Buttigieg stated in a statement on Monday that “we have been encouraging airlines to guarantee family space without imposing on extra charges,” and now some airlines are beginning to make this reasonable move.

USDOT is unveiling a new government dashboard highlighting airline commitments after its four-month review found no airlines previously guaranteed fee-free family seating.

To receive a dashboard green check, airlines must guarantee parents can sit next to children age 13 and younger without being charged additional fees if seats are available at booking and must include that guarantee as part of customer service plans “so that it is backstopped by USDOT enforcement if they fail to deliver,” the department said.

Last week, President Joe Biden urged airlines to follow American Airlines in adopting the commitment as part of a broad effort to crack down on what the White House calls “junk fees.”

“No one should have to pay extra to be seated with their kids,” Biden said on Twitter.

Airlines for America, which represents large U.S. airlines, says its carriers do not charge for family seating but many do not include commitments in customer service plans. Carriers not honor written commitments can face USDOT enforcement actions.

Alaska Airlines said it has “always cared for families on our flights and family seating is something we’ve never charged for.” Frontier said in recent months it took steps to “automatically” seat young children with an accompanying adult. American said its written plan “provides additional clarity.”

USDOT has begun drafting regulations to end family seating fees but that could take years to finalize. The administration plans to send Congress proposed legislation in the coming weeks to end the fees.

Biden first urged airlines in his State of the Union last month to take the action, saying, “Baggage fees are bad enough – airlines can’t treat your child like a piece of baggage.”

In August, U.S. airlines made “significant changes” to customer service plans with nearly all agreeing to offer passengers meals and overnight stays for delays within their control after USDOT first announced a dashboard comparing customer protections.