NEW YORK — A federal judge threw another lifeline to Northwest Airlines yesterday when he blocked flight attendants from striking anytime soon, citing the "vital role" that airlines play in the U.S. economy.

U.S. District Judge Victor Marrero overruled a bankruptcy court judge's decision to let a strike occur.

He noted that Northwest carries 130,000 passengers a day on 1,200 flights and is the lone carrier for 23 U.S. cities and provides half of all airline service to another 20 cities.

"Congress has gone to extraordinary lengths to legislate its view of the vital role that these carriers play for the economy, national security, movement of goods and people, and general well-being of the United States," Marrero said.

Northwest applauded the decision, and called for talks with representatives of about 7,300 active flight attendants. But the union said it won't negotiate unless it has the right to strike.

Later yesterday, the union said it had appealed to the Second Circuit Court of Appeals in New York.

On Aug. 25, Marrero issued a temporary order stopping any strike actions, just hours before flight attendants had said they would begin unannounced, sporadic walkouts. Northwest, already operating under bankruptcy protection, had said a strike could kill it.

The flight attendants said they had a right to strike because on July 31, the company violated labor rules when it imposed pay cuts that they say amount to 40 percent cuts when combined with health insurance increases.

The nation's fifth-largest airline, Northwest had obtained bankruptcy court approval for the move, aimed at saving $30 million a month from flight attendants, who have twice voted down tentative agreements.

Marrero said the bankruptcy court, in permitting a strike, had turned a provision of law — one that allows the airline to impose the cuts to save itself financially — into a "suicide weapon" that could trigger a strike that would drive it out of business anyway.

He said Congress enacted labor laws to specifically avoid disruptive labor disputes and noted that it would be ironic if the two sides used such laws to ruin the company and eliminate jobs.

Marrero also said the flight attendants could someday strike, but only after all the negotiating processes had fully played out.

He said he did not believe the flight attendants had "sufficiently exerted every reasonable effort to settle the parties' dispute without disruption to commerce or to Northwest's operation."

Association of Flight Attendants General Counsel David Borer said union members were frustrated.

"We're dealing with a company that would rather litigate than negotiate," he said, adding that a bankruptcy court ruling which permitted a strike was the correct one because employees have a right to strike when their working conditions are changed unfairly.