Here's the relevant part from the 2016 FAA Reauthorization Act -- "Not later than 1 year after the date of enactment of this Act, the Secretary of Transportation shall review and, if appropriate, establish a policy....". Note the "if appropriate" part. In the end, the transportation department didn't come up with a policy after the review period. There was a separate action by congress called the "Families Flying together Act" in 2015, but it never actually got out of the House aviation committee.