(Adds flight delays in Northeast U.S., Huerta hearing)
WASHINGTON, April 23 (Reuters) - The White House said on Tuesday it would be open to legislation to put air traffic controllers back to work full-time as key U.S. senators demanded more information about the impact of furloughs on safety and air operations.
The Federal Aviation Administration will furlough 47,000 employees for up to 11 days through the end of the fiscal year in September as part of its plan to meet $637 million in required spending cuts. Nearly 13,000 of those are air traffic controllers.
"If Congress has another idea about how to alleviate the challenges that sequester has caused for the FAA and for American travelers, we are open to looking at that," White House spokesman Jay Carney said, referring to $85 billion in federal budget cuts that began in March.
But Carney said the administration's first preference still is for a comprehensive budget deal with a "balanced" package of spending cuts and tax increases.
A bill just to alleviate budget-related problems facing the aviation industry is "a Band-Aid fix," Carney said.
"The fact is there are ... a broad variety of negative effects of sequester" which will have ripple effects on industry, he said, citing cuts to the Head Start pre-school program for children from low-income families, cuts to Meals on Wheels, which delivers meals to people in need, and Defense Department furloughs.
His comments came as U.S. Senate Commerce Committee leaders pressed for more information on how the furloughs and a related plan to close 149 control towers would affect public safety and air operations.
"We are now faced with substantial possible disruptions to the air transportation system," Senate Commerce Committee Chairman Jay Rockefeller, a Democrat, and John Thune, the top Republican on the panel, said in a letter to U.S. Transportation Secretary Ray LaHood and FAA Administrator Michael Huerta.
"The FAA's plan to furlough air traffic controllers and close so many contract towers raises serious safety and operational issues," the senators said.
Carney said the furloughs, which started on Sunday, were necessary because personnel costs make up 70 percent of the FAA's operation budget.
The agency also plans to shut down 149 contract air traffic control towers - where non-FAA employees are employed - at smaller airports on June 15 to save $50 million.
That has raised concerns about the impact on local communities as the airports cut down on flights.
"This is a manufactured crisis. There are many options that the FAA itself and the Department of Transportation as a whole have to avoid this disastrous impact on the traveling public," said Senator Susan Collins, a Maine Republican.
Senators Jerry Moran, a Kansas Republican, and Richard Blumenthal, a Connecticut Democrat, told reporters their bill to prevent the contract towers from closing already had 33 co-sponsors, or one-third of the Senate.
They urged the FAA to delay the furloughs for 30 days to give Congress time to consider legislation on both issues.
Senate Majority Leader Harry Reid outlined a Democratic plan to turn off all sequester cuts for five months by claiming savings from the drawdown of Afghanistan and Iraq wars.
The measure is unlikely to come to a vote before early May, and even then would probably need 60 votes to pass because of procedural hurdles expected from Republicans, who do not want to undo the cuts even though they criticize the way the Obama administration has implemented them.
Although air travelers experienced delays at some airports on Monday, the widespread havoc and long waits that regulators predicted last week largely failed to materialize.
"Yesterday more than 1,200 delays in the system were attributable to staffing reductions resulting from the furlough. There were more than 1,400 additional delays as a result of weather and other factors," the FAA said in a statement.
Still, the FAA on Tuesday showed delays at a number of eastern U.S. airports that it tied to "staffing," including New York's LaGuardia and Ronald Reagan Washington National.
Critics say the administration is using the furloughs and tower closures to demonstrate the impact of the budget cuts caused by the sequestration law.
Rockefeller and Thune's letter contained 18 questions to which they requested a "detailed and immediate response."
Those included how much money the FAA needed to avoid furloughing controllers and closing the towers and what steps the administration has taken to minimize the impact of both actions on the air traffic system.
FAA administrator Michael Huerta is likely to be quizzed on similar topics at a House appropriations subcommittee hearing on Wednesday.
Airlines for America, an industry group, has sued in federal court to stop the furloughs. A decision in that case appears some time away, with no schedule yet for a briefing or oral arguments. (Reporting by Doug Palmer, Roberta Rampton and David Lawder; Editing by Bill Trott, Mohammad Zargham and Bob Burgdorfer)