After 9/11 NORAD said, "Since the tragic events of 9/11, NORADs role which previously was outward-looking now includes monitoring airspace within North America [http://www.norad.mil/50/nutshell.html]." Before 9/11 NORAD said, "The Air Operations Center (AOC) (also known as the Air Defense Operations Center ADOC) maintains constant surveillance of North American airspace to prevent overflight by hostile aircraft. It tracks over 2.5 million aircraft annually [http://www.au.af.mil/au/awc/awcgate/usspc-fs/cmoctrivia.htm]."

See the five articles on NORAD at www.DNotice.org for more on this subject.