did you know, that since 9/11:
The Pentagon now has real-time access to the Federal Aviation Administrations civilian air-traffic control system, allowing the military to immediately begin tracking any plane deemed suspicious by FAA personnel.
... the nations borders are now covered by a chain of overlapping radar arrays jointly overseen by the FAA and the Air Force to provide warning of an inbound threat.
The radar network has transformed ... from one focused primarily on external air threats coming over the pole to a total North American coverage,
the Air Force and Air National Guard have more than doubled the number of alert bases where armed fighter jets sit prepped to launch in seconds. There were just seven of those bases on 9/11, but the number had jumped to 18 by last year under Operation Noble Eagle, with jets and crews standing by for orders from NORAD to scramble and intercept.
the military also has land- and ship-based anti-aircraft missiles that can take down a rogue jet. Commanders, however, prefer to have a pilots eyes on any suspicious aircraft before giving the order to fire.
http://www.nydailynews.com/news/national/missing-jetline-raises-fears-9-11-attack-article-1.1727525