United Airlines Flight 93

United Airlines Flight 93 was an American domestic passenger flight from Newark International Airport in New Jersey to San Francisco International Airport in California that was hijacked by four al-Qaeda terrorists on the morning of September 11, 2001, as part of the September 11 attacks. The hijackers planned to deliberately crash the plane into a federal government building in the national capital of Washington, D.C., but their mission failed when the passengers and crew members fought back, forcing the terrorists to crash the plane into a field near Shanksville in Somerset County, Pennsylvania, preventing them from reaching al-Qaeda's intended target but killing everyone aboard the flight. The airliner involved, a Boeing 757 with 44 passengers and crew, was flying United Airlines' daily scheduled morning flight from Newark International Airport to San Francisco International Airport, making it the only plane hijacked that day not to be a Los Angeles–bound flight.

Forty-six minutes after the flight took off from Newark Airport at 8:42 EDT, the hijackers killed one passenger, stormed the cockpit, struggled with the pilots as controllers on the ground listened in, and moved the remaining passengers and crew members to the rear of the aircraft. Ziad Jarrah, who had trained as a pilot, took control of the aircraft and diverted it back toward the East Coast, in the direction of D.C. Khalid Sheikh Mohammed and Ramzi bin al-Shibh, considered principal instigators of the attacks, have claimed that the intended target was the U.S. Capitol Building, though government officials claim the hijackers could have also intended to crash into the White House.

Meanwhile, as passengers and crew members began calling ground contacts and family members to relay information on the situation, they quickly discovered the hijackers' true intentions. Because the flight's takeoff had been initially delayed by forty-two minutes and the hijackers waited another forty-six minutes into the flight before taking over, it allowed the passengers and crew members to learn through these phone calls that other hijacked planes had already carried out suicide attacks against the Twin Towers of the World Trade Center and the Pentagon shortly before. Realizing that their flight was likely being hijacked as part of a suicide mission, they decided to fight back against the hijackers. In the ensuing struggle, Jarrah chose to crash the plane sooner than he intended to prevent the passengers from taking over the controls, resulting in the plane nosediving at 10:03 into a field near a reclaimed strip mine in Stonycreek Township, near Shanksville, about 65 miles (105 km) southeast of Pittsburgh and 130 miles (210 km) northwest of the capital. One person witnessed the impact from the ground, and news agencies began reporting the event within an hour.