WASHINGTON — After being stuck for 11 hours on a parked airplane during a snow and ice storm, JetBlue passengers found out there's nothing they can do about it.

There are no government regulations limiting the time an airline can keep passengers on grounded aircraft.

The airlines' voluntary code of conduct simply says that during such extraordinary delays, they will make "reasonable efforts" to meet passenger needs for food, water, restroom facilities and medical assistance.

Airlines have blocked attempts to set minimum legal standards for customer service by agreeing to a voluntary code of conduct that they have not always followed.

On Wednesday, hundreds of JetBlue passengers were stuck for as long as 11 hours in parked jets at John F. Kennedy International Airport during the winter storm.

Sean Corrinet of Salem, Mass., spent almost nine hours aboard a JetBlue flight for Cancun, Mexico, that never got off the ground.

"It was like — what's the name of that prison in Vietnam where they held McCain? The Hanoi Hilton," Corrinet said, referring to Sen. John McCain, R-Ariz.

He said the crew passed out bags of chips — the only food available — and periodically cracked the hatch to let in fresh, cool air.

The airline acknowledged that it hesitated nearly five hours before calling for a fleet of buses to unload at least seven jets that spent the day sitting on runways because of the weather and congestion at the gates.

A similar incident happened on Dec. 30, when American Airlines and American Eagle diverted 121 flights found for Dallas to other cities because of thunderstorms. About 5,000 passengers were left sitting on parked aircraft, some for eight hours.

The Dec. 30 incidents prompted American to say it would put a four-hour limit on how long passengers would be kept on grounded planes.

In the late 1990s, the nation's 14 largest airlines joined forces to block a drive by Congress to enact legal protections for passengers, changes that were sought after a series of flight cancellations and delays.

Instead, the airlines agreed to an Airline Customer Service Commitment and incorporated it in their customer agreements, called "conditions of carriage," which are legally enforceable by the customer against the airline.

The airlines said they would notify customers of delays and diversions, try to deliver baggage on time, refund tickets promptly and meet customers' essential needs when they were stuck on parked airplanes.

The airlines, though, didn't agree to limit the amount of time they could keep people inside airplanes that aren't going anywhere.

By February 2001, the airlines were improving their customer service, according to a review by the Transportation Department's inspector general.

A short time later, the airline industry lost record amounts of money. Some sought bankruptcy protection following the Sept. 11, 2001, terrorist attacks, the severe acute respiratory syndrome, or SARS, epidemic, the war in Iraq and rising fuel prices.

By November 2006, customer service had slipped at many airlines, according to Transportation Department Inspector General Calvin Scovell. Many airlines dropped their programs to control quality and measure performance, Scovell reported.

Rep. James Oberstar, D-Minn., chairman of the House Transportation Committee, blamed the Transportation Department for failing to enforce the customer service standards agreed to in 1999.

In the case of JetBlue, Oberstar said the airline didn't have a plan to manage an extreme circumstance.