Southwest Airlines announced Tuesday that future planes will have seats that are a bit wider and C-shaped to give passengers more knee room.

WASHINGTON — The shrinking space on airplanes is surely uncomfortable, but it might also be dangerous for passengers’ health and safety.

Planes are filled with more passengers than ever before. Fliers are older and heavier. Flight attendants warn about an increase in air rage, and experts question if having rows of seats packed closer together might make it harder to evacuate after a crash.

A consumer advisory group set up by the Department of Transportation dove into all those issues this week at a public hearing as part of its role to make suggestions to government regulators. Pennsylvania Attorney General Kathleen Kane chairs the committee

Charlie Leocha, the consumer representative on the committee, said the government sets standards for the conditions for dogs flying as cargo but doesn’t dictate minimum space standards for passengers.

“In a world where animals have more rights to space and food than humans,” Leocha said, “it is time that the DOT and FAA take a stand for humane treatment of passengers.”

Fliers last summer squeezed into the least amount of personal space in the history of flying. In July, U.S. airlines sold a record 87.8 percent of seats on domestic flights, according to the Bureau of Transportation Statics. And that figure does not include all the seats occupied by passengers who redeemed frequent flier miles or airline employees flying for free.

“Unfortunately, the days of the empty middle seat are a thing of the past,” said Julie Frederick, a representative for the American Airlines flight attendants union.

Following the implementation of checked-bag fees in 2008, Frederick said, more and more passengers are carrying on bags, fighting for overhead bin space. That anger carries over through the flight as passengers bump elbows and bang their knees. She said there are more cases of air rage, many of which go unreported.

Questions were also raised if the increased density of seats means passengers won’t be able to evacuate fast enough after a crash.

The Federal Aviation Administration runs various tests including how fast passengers can evacuate a plane.

Cynthia Corbertt, a human factors researcher with the FAA, testified that it conducts those tests using planes with 31 inches between each row of seats. Many passenger jets today have less legroom. For instance, United Airlines has 30 inches of room on some jets; Spirit Airlines offers 28 inches.

David A. Berg, a member of the DOT committee and general counsel for the airline industry’s trade and lobbying group, Airlines for America, asked how airlines would respond if the government created a new rule requiring a minimum amount of legroom.

“If airlines are forced to reduce the number of seats,” Hansen replied, “inevitably there would be an increase and it would price out part of the traveling public.”