The US Department of Transportation would be legally required to set minimum airline seat size and pitch standards under legislation now moving through the US House of Representatives.

USA Today reports that the requirement is included in the current Federal Aviation Administration Reauthorization Bill.

The transportation department also is studying how quickly planes can be evacuated from ever more cramped airline cabins, although the FAA recently said that it has no evidence “current seat dimensions (width and pitch) hamper the speed of passenger evacuation, or that increasing passenger size creates an evacuation issue”.

In the past 15 years, airlines have crammed an average of 8 per cent more seats in aircraft cabins, according to the industry consulting firm ICF.

“The only way to change things is through the market,” said Pat Askew, director of aviation at design firm HKS. “Passengers must be more vocal about the unacceptability of tight seating and be willing to pay more for a ticket, like premium economy.”

Some experts worry, however, that airlines could respond to restrictions on seat size in ways that passengers won’t like.

“If airlines can’t reduce space, padding and comfort will be the first to go,” said Zander Futernick, founder of ZED Aerospace, noting that some low-cost carriers have already made such changes after reducing seat size to a bare minimum.