Rep. Jerrold Nadler (D-N.Y.), the sponsor of the bill, said the only recourse families have today is relying on other passengers to switch seats, which he said is an "inconvenience" and "not an efficient business practice."

"Air travel is stressful enough for families without adding new worries," Nadler said Thursday.

"Families should not be stuck paying hidden fees, or buying 'premium' seats, simply because they wish to be seated together on crowded flights," he said. "It is positively absurd to expect a two or three-year-old to sit unattended, next to strangers, on an airplane. It is up to air carriers to make their seating policies clear and easily accessible to the public."

Under the Families Flying Together Act, the Department of Transportation would direct air lines to "establish a policy to ensure, to the extent practicable, that a family that purchases tickets for a flight with that air carrier is seated together during that flight."

It would also require airlines to make their policy available to the public on their websites.

Reps. Janice Hahn (D-Calif.), Carolyn Maloney (D-N.Y.), and Charlie Rangel (D-N.Y.) are cosponsors of the bill.