Airlines would be required to disclose fees for luggage or for passengers to sit next to their children prior to ticket purchase under a regulation proposed Monday by the Biden administration.

The action, proposed by the US Department of Transportation (DOT), responds to consumer complaints about hidden fees for services no longer typically included in the base fare.

Besides surcharges for checked or carry-on baggage and fees to sit with a child, airlines would also be required to disclose up front fees for changing or canceling a flight, according to a DOT press release.

The proposed rule, which will be open up to a 60-day public comment period, would also apply to third-party sellers of airline tickets, or online websites that list fares, DOT said.

"Airline passengers deserve to know the full, true cost of their flights before they buy a ticket," said US Transportation Secretary Pete Buttigieg.

"This new proposed rule would require airlines to be transparent with customers about the fees they charge, which will help travelers make informed decisions and save money."

Airlines for America (A4A) said the industry already provides customers with clear information on ticket pricing, including taxes and government fees, which account for more than 20 percent of many ticket prices for domestic flights, said a spokesperson for the group, which represents large US carriers.

"A4A member passenger airlines -- which are fierce competitors -- already offer transparency to consumers from first search to touchdown," the group said.

"A4A members offer a range of options -- including fully refundable fares -- to increase accessibility to air travel and to help customers make ticket selections that best fit their needs," the group added.

"In addition to the total cost, the terms of ticket selection for these options are stated at the time of purchase."