Airlines would be required to improve accessibility for travelers with disabilities on more of their planes under a new federal proposal.

The U.S. Department of Transportation is seeking public comment on a plan calling for all new, single-aisle aircraft to feature accessible lavatories.

Current rules only mandate accessible restrooms on planes with more than one aisle. But the federal agency said that single-aisle aircraft are increasingly being used on long-haul flights.

“The inability to use the lavatory on long flights can present significant challenges to passengers with disabilities, and poses a deterrent for some passengers with disabilities to traveling by air,” notes the Transportation Department proposal released Monday.

The agency is looking to amend its existing Air Carrier Access Act regulation. Under the plan, new single-aisle aircraft that seat 125 or more passengers must have lavatories with accessible toilet seats, assist handles, faucets, attendant call buttons and door locks, among other features. Airlines would also be required to have an onboard wheelchair with improved safety and maneuverability that could provide entry into the aircraft lavatory.

The proposed rule stipulates that flight attendants be trained to assist individuals with disabilities to get from their seat to the lavatory using the onboard wheelchair. What’s more, information about the accessibility of an aircraft’s lavatories would be available on airline websites, on the plane and upon request so that travelers can plan accordingly, the Transportation Department said.

With the notice issued Monday, federal officials are not requesting any change to the physical size of lavatories on single-aisle aircraft. But, they said that an advance notice of proposed rulemaking is expected in the near future to solicit feedback on the idea of mandating that lavatories on new single-aisle aircraft match the larger size found on planes with two aisles.

The Transportation Department estimates that it would cost $1,000 per lavatory to make the improvements the agency is seeking.

The current proposal will be up for public comment for 60 days.