WASHINGTON - Stinky toilets, crying babies, airless cabins. The Obama administration said yesterday that passengers don't have to take it anymore. It ordered airlines to let people get off planes delayed on the ground after three hours.

Airlines could be fined $27,500 per passenger for each violation of the three-hour limit.

Transportation Secretary Ray LaHood said the three-hour limit and other new regulations, which would take effect in about four months, were meant to send a message to airlines not to hold passengers hostage on stuck planes. Coming on the eve of the busy holiday travel season, the announcement was hailed by one consumer advocate as "a Christmas miracle."

The airline industry said it would comply with the regulations but predicted the results would be more canceled flights and more inconvenience for passengers.

"The requirement of having planes return to the gates within a three-hour window or face significant fines is inconsistent with our goal of completing as many flights as possible. Lengthy tarmac delays benefit no one," said James May, president and chief executive officer of the Air Transport Association.

LaHood dismissed that concern. "I don't know what can be more disruptive to people than to be stuck sitting on a plane five, six, seven hours with no explanation," he said at a briefing.

This year through Oct. 31, there were 864 flights with taxi-out times or flight diversions of three hours or more, according to the Bureau of Transportation Statistics. Transportation officials, using 2007 and 2008 data, said that, on average, about 1,500 domestic flights a year carrying about 114,000 passengers were delayed more than three hours.

Last month, the department fined Continental Airlines, ExpressJet Airlines, and Mesaba Airlines $175,000 for their roles in a nearly six-hour tarmac delay in Rochester, Minn.

In August, Continental Express Flight 2816 en route to Minneapolis was diverted to Rochester because of thunderstorms. Forty-seven passengers were kept overnight in a cramped plane because Mesaba employees refused to open a gate so they could enter the closed airport terminal. That was the first time the department had fined an airline for actions involving a ground delay.

Under the new regulations, the only exceptions to the requirement that planes must return to the gate after three hours are for safety or security reasons, or if air-traffic control advises the pilot in command that returning to the terminal would disrupt airport operations.

The rules would apply to domestic flights. U.S. carriers operating international flights departing from or arriving in the United States must specify, in advance, their own time limits for deplaning passengers. Foreign carriers do not fly between two U.S. cities and are not covered by the rules.

Tarmac strandings have mostly involved domestic flights, but the department is studying extending the three-hour limit to international flights, LaHood said.

Airlines will be required to provide food and water for passengers within two hours of a plane being delayed on a tarmac, and to maintain operable lavatories. They must also provide passengers with medical attention when necessary.

Airlines will also be prohibited from scheduling chronically delayed flights. They must designate an employee to monitor the effects of flight delays and cancellations. And they would have to post flight-delay information on their Web sites. Carriers that fail to comply could face government enforcement action for using unfair or deceptive trade practices.

Provisions sponsored by Sens. Barbara Boxer (D., Calif.) and Olympia Snowe (R., Maine) in pending legislation would also impose a three-hour limit, but the new regulations go even further, giving passenger-rights advocates many of the reforms they've sought for years.

"No more will they be able to strand passengers for over three hours in hot, sweaty, metal tubes," said Kate Hanni, founder of Flyersrights.org. Hanni, who called the rules "a Christmas miracle," was stuck on an American Airlines jet in Austin, Texas, for more than nine hours in December 2006.

Past efforts to address the problem have fizzled in the face of industry opposition and promises of reform.

Congress and the Clinton administration tried to act after a January 1999 blizzard kept Northwest Airlines planes on the ground in Detroit, trapping passengers for seven hours. Some new regulations were put in place, but most proposals died, including one that airlines pay passengers who are kept waiting on a runway for more than two hours.

The Bush administration and Congress returned to the issue three years ago after several high-profile strandings, including a snow and ice storm that led JetBlue Airways to leave planes full of passengers sitting on the tarmac at New York's Kennedy International Airport for nearly 11 hours.

After those incidents, DOT Inspector General Calvin Scovel recommended that airlines be required to set a limit on the time passengers have to wait out travel delays grounded inside an airplane.