WASHINGTON (AP) — The Federal Aviation Administration is creating a new air traffic system that officials say will be as revolutionary for civil aviation as was the advent of radar six decades ago. But the program is at a crossroads.

It's getting harder to pry money out of Congress. The airline industry is hesitating over the cost of equipping its planes with new technology necessary to use the system. And some experts say the U.S. could lose its lead in the manufacture of high tech aviation equipment to European competitors because the FAA is moving too slowly.

Seventy-five years ago this week the federal government, spurred by the nascent airline industry, began tracking planes at the nation's first air traffic control centers in Newark, N.J., Chicago and Cleveland.

The original group of 15 controllers, relying on radioed position reports from pilots, plotted the progress of flights using blackboards, maps and boat-shaped weights. Air traffic control took a technological leap forward in the 1950s with the introduction of radar. That's still the basis of the technology used today by more than 15,000 controllers to guide 50,000 flights a day.

Under FAA's Next Generation Air Transportation System program, known as NextGen, ground radar stations will be replaced by satellite-based technology. Instead of flying indirect routes to stay within the range of ground stations, as planes do today, pilots will use GPS technology to fly directly to their destinations.

Planes will continually broadcast their exact positions, not only to air traffic controllers, but to other similarly equipped aircraft within hundreds of miles. For the first time, pilots will be able to see on cockpit displays where they are in relation to other planes and what the flight plans are for those other aircraft. That will enable planes to safely fly closer together.

When planes approach airports, precise GPS navigation will allow them to use more efficient landing and takeoff procedures. Instead of time-consuming, fuel-burning stair- step descents, planes will be able to glide in more steeply with their engines idling. Aircraft will be able to land and take off closer together and more frequently, even in poor weather, because pilots will know the precise location of other aircraft and obstacles on the ground. Fewer planes will be diverted.

Pilots and airline dispatchers will be able get real-time weather information. Computers will spot potential weather conflicts well in advance so that planes can be rerouted. And, controllers will do a lot less talking to pilots. Many instructions now transmitted by radio will instead be sent digitally to cockpits, reducing the chance of errors.

Together, the suite of new technologies and procedures being phased in will significantly increase the system's traffic capacity, FAA officials predict. That's critical if the number of passengers traveling annually on U.S. airlines grows from an estimated 737 million this year to over 1 billion a year in the next decade, as the FAA forecasts.

And, the FAA predicts, NextGen will save significant time, fuel and money. It also will reduce greenhouse gas emissions and noise.

"It really is a revolution in air transportation," Deputy FAA Administrator Michael Huerta said in an interview. "The decisions we're making in the next several years will set the foundation for the next 75 years of air traffic control."

Paying the tab for NextGen — estimated at as much as $22 billion for the government and another $20 billion for the airline industry through 2025 — may be FAA's biggest hurdle. The program has widespread support in the Obama administration and Congress, but it isn't immune to budget cuts in the current climate of austerity. The House wants to reduce FAA's budget authority by $1 billion a year over the next four years, while the Senate has favored higher funding.

Even longtime NextGen supporters like Sen. Patty Murray, D-Wash., chairman of the Senate Appropriations Committee's transportation subcommittee, warn that full funding is no longer automatic.

"We need to see a realistic strategy for funding NextGen," she told FAA Administrator Randy Babbitt at a May hearing. "To date, the FAA has filled its budget request with a laundry list of programs and development activities, and a vague promise that somehow the agency will achieve its goals by 2018. But that approach is not enough this year."

If funding is reduced, some elements of NextGen could be delayed. There is no date for completion of the entire program, which officials say is constantly evolving.

Airlines support NextGen, but they're wary of FAA's track record of changing directions after investments have been made. FAA began its modernization program in 1981. It was branded as NextGen in 2003.

"We want to leverage the technology we have today before we add more technology and more cost," Delta Air Lines Inc. CEO Richard Anderson told reporters in April.

Airlines also want proof NextGen is ready to produce tangible benefits, that it "is not just a big sales program by the avionics (aircraft electronics) sales people," he said.

And, airlines want the government to help underwrite the cost of equipment they're going to be required to buy.

"This is not a cost the airlines can, or should, absorb," Glenn Tilton, chairman of United Continental Holdings Inc. told an aviation luncheon in Washington in November.

Airlines should "recognize you as an industry get benefits from this," Huerta said. "Those benefits are something you should be prepared to pay for."

Yet, some sort of federal help — loan guarantees, for example — may be reasonable, he said.

"The very valid question they are asking is, shouldn't the government have a stake in the game as well?" Huerta said. He heads an FAA-industry task force expected to develop a recommendation in September.

Some airlines are moving ahead. Alaska Airlines is using GPS precision landing procedures at Juneau International Airport, where mountainous terrain and frequent low visibility conditions were routinely forcing cancellations. The airline estimates it would have cancelled 729 flights last year into Juneau if not for the new approaches.

Results have been mixed elsewhere. Southwest Airlines has spent $175 million on equipment and pilot training so it could make use of optimized landing approaches. But so far only 11 of Southwest's 72 U.S. destinations are set up for the advanced procedures. FAA hasn't yet approved new procedures for the remaining airports. And there's no timetable for when they will come online. It can take the agency as long as two years to approve a new procedure for a single runway.

Southwest wants to see more results before making further investments, spokeswoman Brandy King said.

The U.S. isn't alone as it transitions to a new air traffic system. Much of the world is adopting GPS technology. But the U.S. accounts for nearly 40 percent of global air traffic and has a robust private aircraft community not found in most countries, adding complexity to the program.

The FAA has set a deadline of 2020 for airlines to install key equipment that will tell controllers and other aircraft the location of their planes. But the agency has been slow to set technical standards and a deadline for other equipment that will be necessary to realize the full benefits of NextGen, industry officials said.

The European Union is further along in developing equipment standards, industry officials said. As a result, the world may wind up adopting standards developed by the EU, rather than the U.S., said Hans Weber, president of TECOP International Inc., an aviation technology management firm in San Diego.

In the past, "we've basically set the standard worldwide for air traffic management. Our companies were always first to market, giving them better profit margins," Weber said. "That's what we're at risk of losing. We are risking default to the Europeans."