The way Americans fly is changing — even if most consumers can’t tell yet. NextGen is a federal program modernizing the airline industry. It’s supposed to save fuel, cut emissions and safely fit more planes into existing airspace. And it’s here in Phoenix in a big way.

NextGen is kind of a holistic term. It includes stages of technical upgrades and new flight practices headed by the Federal Aviation Administration. It’s supposed to be fully in place by 2025.

According to FAA Deputy Administrator Michael Whitaker, the agency is less than two years away from transforming radar at every FAA location across the country. 

Imagine traditional radar screen with that arm sweeping like a clock hand. Then forget it.

"We’ve moved from that two-dimensional picture to a three-dimensional picture, with greater visibility and great ability to create air routes," Whitaker said, "and ultimately we’re going to be going to a four-dimensional picture where we’re able to time the flights from the time they leave the airport, all the way until the time that they land."

That’s what happens as the FAA moves from the old, ground-based radar system to one that’s run by satellites and GPS. Eventually, when planes take off in, say, Francisco and Las Vegas, air traffic control will already know what order they’ll land in Phoenix.

One of the biggest innovations in effect now sounds simple: how planes approach airports for landing. The term is called Optimized Profile Descents.

"The pilot basically reduces engine power over 100 miles from the airport," Whitaker said. "So there’s a very significant savings of fuel just from that act alone. The engines basically go to an idle setting."

That creates a constant descent, instead the old way of stepping down then leveling off in a series. These new descents are in place at airports across the country — including Phoenix’s Sky Harbor. Up to 90 percent of all flights coming into the airport use these new descents. That makes Sky Harbor one of the more active NextGen airports in the country. It saves carriers about $2 million each year in fuel at Sky Harbor alone. And that's not the only benefit, explained US Airways pilot Dave Surridge.

"Just as important, reductions in emissions," he said.

Surridge said US Airways has been a leader with these new descents. But other aspects of NextGen probably won’t come online as quickly. The entire NextGen overhaul is expected to cost about $40 billion, most of it paid for by the FAA. But the airlines will be on the hook for certain costs, including updating technology on their aircrafts.

"The future goes on, those things will start paying off," Surridge said, "but in the short term, there’s not a big payoff."

NextGen’s rollout is mostly on track but it has been slowed by sequestration and even the recent government shutdown. A possible second shutdown in January could also hamper progress.

Another worry from critics is that more automation could mean that pilots simply forget how to fly without it. In fact, a recent FAA study says pilots do rely too heavily on automation. But it also says that pilots are usually able to fix problems as they arise in flight or with simulators. And that makes sense to retired pilot Ron Logan.

"Machines can only do so much," he said. "You have to have somebody up there thinking, in my opinion."

Especially as NextGen adds more planes — and pilots — to America’s airspace.