U.S. airlines on Friday sought a federal court order to block extended furloughs for air traffic controllers, a process scheduled to begin Sunday that they say will snarl the nation’s aviation system.

Federal officials estimate that about a third of all passengers will face delays, with up to 6,700 flights arriving late at more than a dozen major airports each day. By contrast, on the worst travel day of 2012, when severe weather crippled the system, about 3,000 flights were delayed.

“It will not be very long until the system comes to a grinding halt, much like you see with a severe weather event,” said Lee Moak, head of Air Line Pilots Association. “It would be like having Hurricane Sandy in the north and Hurricane Katrina in the south at the same time. The air system is not a light switch. Once it starts, it takes days and days to recover.”

Airline industry officials said they expected it would be at least a week before their request gets a court hearing. Once the furlough plan goes into effect on Sunday, they predict a “snowball effect” that would quickly turn air travel into a chancy exercise.

“There is still money at the [Federal Aviation Administration] to pay air traffic controllers,” Moak said. “Whoever is making that decision in the administration, they are using this as a political football.”

The plan announced by Transportation Secretary Ray LaHood and FAA Administrator Michael Huerta was described as an unavoidable step to comply with the sequestration mandates. It would require air traffic controllers to take one unpaid day off for every 10 working days.

LaHood told reporters Thursday that he had looked “far and wide” for ways to cut the FAA budget before turning to the more than 14,000 controllers whose pay is the agency’s single largest expense. The furloughs would save about $200 million of the $637 million the FAA needs to trim from its budget this fiscal year under sequestration.

“We cannot avoid furloughs,” LaHood said.

Huerta said the worst delays would come at major hub airports, including the three that serve New York City, two that serve Chicago, as well as in San Diego, Los Angeles, San Francisco, Miami, Fort Lauderdale, Charlotte, Atlanta and Philadelphia.

The FAA plans to delay takeoff of planes from originating airports so they do not have to circle those hub airports while short-staffed control facilities manage the flow.

Huerta said FAA calculations showed the worst delays — up to 3 1 / 2 hours — were likely in Atlanta. He said more than two-hour delays were possible at Chicago’s O’Hare International Airport, with an hour and 20 minutes at New York’s LaGuardia Airport. At the rest of the hard-hit airports, he said delays would be about an hour or less.

Bad weather could compound the problem, he said.

“We are not going to sacrifice safety,” Huerta said. “There are about a dozen airports that will see heavy to moderate delays, which could be similar to what we would experience during a significant summer thunderstorm.”

Nicholas E. Calio, president of the industry trade group Airlines for America, said the airlines pressed for controllers to be designated as essential personnel and exempted from the sequestration cuts. Two years ago, when a congressional deadlock caused the FAA to shut down, controllers were deemed vital and kept on the job.

Calio said his group would turn to Congress to seek an exemption.

“We were told that the administration would not support any such legislation unless it specifically solves the entire sequestration problem,” he said. “The FAA does have flexibility in how it implements its sequester cuts. Our point is the cuts can be made somewhere else. Airlines, aviation and our customers should not be part of a political battle.”

The political finger pointing continued Friday on Capitol Hill.

Senate Transportation Committee Chairman John D. Rockefeller IV (D-W.Va.) said the furloughs came because “House Republicans refused to work with the Senate and the president to prevent these indiscriminate reductions.

He also criticized the FAA.

“I am deeply disappointed that the agency has failed to inform the public on how dramatically their travel plans will be impacted in the days and weeks ahead,” he said.

The FAA also took heat from Rep. Bill Shuster (R-Pa.). 

“The FAA’s management of sequestration is quickly going from bad to worse,” he said.  “Given that the FAA’s budget increased more than 100 percent over the last 15 years, finding 5 percent in savings shouldn’t need to significantly impact our nation’s aviation operations.”

The controllers union president, Paul Rinaldi, asked Congress and the White House to find an alternative to the furloughs.

“No one wants to see these furloughs be implemented, least of all the controllers who want to be on the job, making the system work,” Rinaldi said.