Next Gen is the FAA's plan to completely redo the national air traffic control system. Under Next Gen, each aircraft would be required to carry a GPS receiver, and upon interrogation from ground radar the aircraft would report it's position according to GPS.
Next Gen would require every aircraft to be equipped with a $25,000 GPS box, at the owner's expense. Benefit is better accuracy. GPS is accurate to a few feet. Ground radar is accurate to only a few miles. Knowing that the radar positions are only accurate to a few miles, air traffic controllers keep planes spaced apart in the sky by ten miles or more. It is claimed that Next Gen would permit closer spacing, making more room in the sky to absorb the ever increasing load of air traffic. And the equipment manufacturers are more than pleased with the thought of selling all those expensive GPS boxes.
And now, according to Aviation Week, all this goodness is on hold because Congressional austerity programs won't pay for Next Gen. Oh woe.
In actual fact, there is plenty of sky for any amount of aircraft using today's tried and true radars. The bottleneck is at the airports. We only have about 50 big airports into which ALL the scheduled air traffic goes. These airports can only handle 60 planes an hour. That limit is set by common sense. You want the plane that landed to slow down and turn off the active runway before you allow the plane behind him to land. Just in case the landing aircraft blows a tire, skids off the runway, or worse (Asiana 214 anyone?) . That takes about a minute.
Likewise you want the plane taking off to make it safely into the air before you allow the plane behind to start his takeoff roll. This takes about a minute. So the airports are the limit to air traffic, not a lack of sky to hold the planes. No amount of pricey Next Gen GPS will do anything to let the airports handle more traffic than they do now.