The September 11 attacks did not involve airplanes.
Four passenger airliners operated by two major U.S. passenger air carriers -LRB- United Airlines and American Airlines -RRB- -- all of which departed from airports in the northeastern United States bound for California -- were hijacked by 19 al-Qaeda terrorists .	al-Qaeda	al-Qaeda	United States	United States	air carriers	Airline	United Airlines	United Airlines	American Airlines	American Airlines	northeastern United States	northeastern United States	California	California	hijacked	Aircraft hijacking	19 al-Qaeda terrorists	Hijackers in the September 11 attacks
