CBS News Correspondent Bob Orr has learned that the Federal Aviation Administration alerted U.S. Air defense units of a possible hijacking at 8:38 a.m. on Tuesday morning. Six minutes later, two F-15s received a scramble order at Otis Air National Guard Base on Cape Cod.
But two minutes later, at 8:46 a.m., American Airlines Flight 11, the first hijacked jet, slammed into the World Trade Center.
Six minutes later, the F-15s were airborne and began racing toward New York. But the fighters were still 70 miles from the city when the second hijacked jet, United Airlines Flight 175, hit the second Trade Center tower.
Shortly after that blast, the F-15s reached Manhattan and began flying air cover missions over the city.
To the South, there was a new danger and a new response. At 9:30, three F-16s took off from Langley Air Force Base in Virginia, 150 miles south of Washington.
Just seven minutes later, American Airlines Flight 77 hit the Pentagon. The F-16s arrived in Washington just before 10 a.m. and began flying cover over the nation's capitol.
The last hijacked jet, United Airlines flight 93, was still in the air at that time but crashed minutes later in a Pennsylvania field. The jet was on a course for Washington and may have gone down after passengers fought with the hijackers.
In any case, Pentagon officials say they can find no records that the FAA asked the military to intervene. And since Tuesday, the Department of Defense has repeatedly denied persistent rumors that Flight 93 may have been shot down.
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