On September 11, 2001, under clear skies across the northeastern United States, the seven crew members of Flight 93 prepared for a nonstop trip from Newark, New Jersey, to San Francisco, California, while thirty-three passengers traveled for ordinary reasons and four others boarded intending to hijack the aircraft. The terrorist organization al-Qaeda had begun planning the attack in 1999, but Flight 93 departed more than 25 minutes late because of heavy air traffic even as the first three hijacked planes left on schedule. Four minutes after Flight 93 took off, hijacked American Airlines Flight 11 struck the North Tower of the World Trade Center in New York City, and at 9:03 am United Airlines Flight 175 hit the South Tower. At 9:28 am, forty-six minutes into the flight, the terrorists aboard Flight 93 attacked the cockpit, and air traffic controllers in Cleveland, Ohio, heard the captain or first officer shout, "Mayday! Get out of here!" The hijackers seized control of the aircraft and turned it southeast toward Washington, DC. At 9:37 am, hijacked American Airlines Flight 77 crashed into the Pentagon in Arlington, Virginia, and five minutes later the Federal Aviation Administration ordered every aircraft over the nation to land at the nearest airport; in response, 4,500 aircraft landed safely without incident.