Every commercial flight that takes off from the United States is currently monitored by a radar-based ground system that has been in place since WWII.

However, with the number of US passengers set to rise to one billion per year by 2020, the Federal Aviation Administration (FAA) is planning a move to a new satellite-based system, called Next Generation Air Transportation System, or NextGen.

According to the FAA, the system will make air travel faster, safer and cheaper. New software and equipment capabilities have been added to airports across the country, and by 2018 the FAA expects the system to have already cut flight delays by 35% -- saving 1.4 billion gallons of fuel, reducing costs by $23 billion and carbon emissions by 14 million tons. The change is scheduled to be completed by 2025.

The satellite GPS system will give pilots and controllers the exact locations of planes and how near they are to each other. This allows more planes to be in the air more safely and able to fly more direct routes. And, because the GPS shows terrain regardless of the weather, it will also reduce flight delays.

Airlines, facing bankruptcy and a sluggish economy, have been slow to implement the upgrades needed, both to the planes and ground equipment and training. According to the Department of Transportation, some of the software components are already running a staggering $300 million over budget.

Congress has so far failed to pass a long-term bill for the FAA. With the cost of NextGen around $20 billion, The Us government may not be interested in passing it for a while to come.