NextGen's satellite-based air traffic control system will update an airplane's location once every second, compared to just once every 12 seconds for current radar-based systems, according to an official with ITT Corp., the lead contractor on the massive project. But the system is not without controversy: The FAA wants every aircraft to be equipped with GPS devices by 2020, and the $16,000 price tag could be prohibitive for general aviation. "We believe FAA can take some steps to make the electronics much more affordable," says Randy Kenagy of AOPA's government affairs division. Private companies are stepping in to help make the technology more affordable. MITRE Corp., for instance, is developing ADS-B avionics for gliders with a materials cost of just $375.