Civilian aircraft traffic resumes in the United States after the September 11 attacks.

September 11 attacks

2001 Islamist terror attacks in the U.S.

The September 11 attacks, also known as 9/11, were four coordinated Islamist terrorist suicide attacks by al-Qaeda against the United States in 2001. Nineteen terrorists hijacked four commercial airliners, crashing the first two into the Twin Towers of the World Trade Center in…