THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
MILES O'BRIEN, CNN CORRESPONDENT (voice-over): It is Tuesday morning over America and the skies are crowded as ever. More than 4,500 flights are in the air. A typical day or so this FAA radar replay implies.
The seats filled with salesmen on their way to a big presentation, students headed home, families to Disney. But somewhere in this dizzying, disorienting field of blue 19 passengers sat in their seats on four separate flights reviewing a sinister, synchronized plan that would change aviation, change America forever.
No, it was not a typical morning. And there was at least one subtle clue. Two Arab friends who insisted on sitting far apart on a nearly empty plane. Odd, thought an airline employee -- odd indeed.
Boston's Logan Airport -- Terminal B, Gate 26. American Airlines Captain John Oganowski gave the signal to push back his Boeing 767. Flight 11 was bound for Los Angeles.
This father of three and part-time farmer had just celebrated his 52nd birthday.
Gate 19 -- the next terminal -- 22 year old Lisa Frost and 64 others boarded another L.A.-bound 767 -- United Airlines Flight 175. Lisa was headed home to celebrate her recent college graduation -- number one in her class.
American 11 taxied ahead of United 175 to the active runway. They were both airborne by 8:15. No one knew that among the seated passengers there were hijackers -- five men on each flight ready to take control of the planes.
(on camera): Here's how it all unfolded according to this computer replay of the FAA radar information. American Flight 11 took off out of Boston and flew due west across Massachusetts and into Upstate New York. United 175 flew southwesterly across Connecticut. But 20 minutes into both flights things changed drastically.
American 11 turned due south very sharply. United 175 also went off course toward New York. At about the same time the transponders on both aircraft were turned off. That's a crucial device which sends important information and adds it onto the radar blip, which the controllers see -- things like the type of aircraft and most importantly the altitude.
(voice-over): When flight controllers in FAA radar rooms in New Hampshire and New York saw this they immediately surmised it was a hijacking and also assumed it would end like other hijackings -- at an airport. So they concentrated on keeping other planes away from the wayward flights. They tried repeatedly to contact the crew on the radio to no avail.
Just as Flight 11 took its ominous turn another American Airlines plane -- a 757 -- departs out of Washington's Dulles Airport bound for Los Angeles.
CNN has learned that as the passengers began to board an American Airlines employee struck up a conversation with two Arab male passengers who said they were friends. One of them had a fist class boarding pass for seat number 2B -- the other in coach.
The American Airlines employee asked, "Why don't you guys sit together?" She felt that was odd -- it was. Those two men have been named by the FBI as two of the five hijackers including Hani Hanjour who is believed to have been trained as a pilot.
Also on the flight -- a group of school children on a field trip, a husband and wife flight attendant team and noted attorney Barbara Olson. Nothing seemed amiss until four hijackers armed with knives took control of the aircraft.
JOHN WHILY, PILOT: It's a fragile piece of material. It is not designed to keep people out that are determined, much less a group of individuals. So a group of determined individuals are going to be able to assault a cockpit and gain entry with the current door.
O'BRIEN: 8:29 a.m. -- American Flight 11 remains in serious trouble and has a new course -- the twin towers in New York City. But Captain Oganowski tries to signal air controllers of his plane's fate by keeping a microphone open for those on the ground to hear. The hijackers have stabbed several flight attendants but not before one of them can phone American's headquarters back in Dallas.
The plane drops to below 1,000 feet, speeding closer to its target. Three flights, 14 hijackers and the drama in the sky still isn't over.
(on camera): There is a fourth flight -- United Airlines Flight 93 -- a 757 which took off from Newark, New Jersey at 8:44 in the morning bound for San Francisco with 35 passengers and crew -- among them four hijackers.
As it becomes airborne, American Airlines Flight 11, the first flight out of Boston, is only a minute away from striking the first tower of the World Trade Center.
Meanwhile United 175 is not far behind. It flies to the south and then over New York Harbor, taking aim at the south tower.
(voice-over): It was 8:45, only 20 minutes after controllers realized it was hijacked, American Airlines Flight 11 crashes into the northern tower of the World Trade Center.
WHILY: You have to know that these guys were not trying to land these things in a crosswind on a short runway in inclement weather. They were going after big targets.
O'BRIEN: On United Flight 175 passengers begin to make phone calls to their loved ones. Shortly before 9:00 a.m., 12 minutes after American Flight 11 has impacted, United 175 is set for a collision course with the southern tower of the World Trade center.
Meanwhile, according to one family member, on United 93 the hijackers, who had bought first class tickets, reported told the passengers they were going to die and to call their loved ones to say good bye.
Thirty-one year old Jeremy Glick called his wife, staying on the line as long as he could. Glick told his wife a flight attendant had been stabbed and that the four hijackers had moved them to the back of the plane.
Tom Burnett also called his wife. The 38-year-old executive told her the male passengers had taken a vote and were not going to give up despite the bloodshed onboard by their attackers.
DEENA BURNETT, WIFE OF CRASH VICTIM TOM BURNETT: They said they had already knifed a guy. They're saying they have a bomb -- please call the authorities.
O'BRIEN: When Glick's family confirmed what another passenger had heard -- that a plane had already struck the World Trade Center -- Glick dropped the phone then returned to tell his family the male passengers had taken a vote to attack the terrorists.
At 9:03 a.m., 48 minutes after takeoff, United Flight 175 slammed into the south tower of the World Trade Center.
Twenty-two minutes later at 9:25 a.m. there is violence on American Airlines Flight 77. Passenger Barbara Olson calls he husband, Solicitor General Ted Olson, from the back of the plane. While huddled with the other passengers she told her husband the five hijackers had knives and box cutters and had taken the pilot out of the cockpit.
(on camera): Once again the transponder was turned off so the radar information is somewhat misleading. But controllers believe the plane didn't stray far from the Washington air space, flying around the area and flirting with the restricted air space near the Capitol and the White House.
About 40 minutes after the last collision at the World Trade Center, American Flight 77 was headed directly toward the Pentagon.
Meanwhile, United Flight 93 was still on course toward San Francisco and right as it got toward Cleveland it made a sudden course change -- a 180. Its transponder went off at about the same time and this flight was headed directly toward Washington. (voice-over): At 9:45 American Flight 77 crashed into the Pentagon.
Three downed planes and as United 93 headed east air traffic controllers watching the flight reported they could hear screaming over the cockpit radio -- one voice yelling repeatedly, "Get out of here." And then later an accented voice apparently making a public address announcement to the passengers, "There is a bomb on board. Stay quiet. We are meeting their demands. We are returning to the airport."
By 10:10 a.m. it was all over. An hour and fifteen minutes after United Flight 93 departed Newark airport, shortly after the men had voted to attack the terrorists, the 757 crashed in a remote cornfield in rural Pennsylvania.
(on camera): When it became clear these were not conventional hijackings with tense but safe landings and instead suicide missions, the FAA took some unprecedented action. It grounded all flights on the ground that had not departed and ordered flights in the air to land immediately.
It's an amazing sight to watch the radar replay of all of this as the 4,500 dots disappear. In little more than an hour nothing was flying over the U.S. -- the skies silent, a nation stunned.
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