http://www.networkworld.com/news/2013/011113-hacke...
By spoofing those signals, Haines said he could create fake "ghost planes."
"If I can inject 50 extra flights onto an air traffic controller's screen, they are not going to know what is going on," he told NPR. "If you could introduce enough chaos into the system - for even an hour - that hour will ripple though the entire world's air traffic control."