The Department of Transport (DoT) have unveiled a new dashboard to put public pressure on US carriers to address concerns, with the platform highlighting the fact that so far, just American, Alaska and Frontier airlines allow families with young kids to sit together for free.
US Transportation Secretary Pete Buttigieg said: "Parents traveling with young kids should be able to sit together without an airline forcing them to pay junk fees.
"We have been pressing airlines to guarantee family seating without tacking on extra charges, and now we're seeing some airlines start to make this common-sense change.
"All airlines should do this promptly, even as we move forward to develop a rule establishing this as a requirement across the board."
The family seating dashboard aims to show "a clear comparison of services the airlines have committed to provide" and avoid "airlines' confusing claims on family seating".
The DoT guidance added: "To receive a green check on the dashboard, an airline must guarantee that parents can sit next to children age 13 and younger for free if adjacent seats are available when they book".
This must be included in an airline's customer service plan so it is enforceable by the DoT.
Most airlines in the US currently say they will try to accommodate seating requests, but only some guarantee children will be seated next to an accompanying adult without a fee.