What is known is: a Boeing 757, American Airlines Flight 77, which that had departed from Dulles International airport in Virginia en route to Los Angeles at 8:20 AM, turned off its transponders at 9:02 AM, and at 9:38 AM crashed into the Pentagon. The FBI determined the identities used by five hijackers.

There were no communications whatsoever with the 2 airline pilots after they climbed to their cruising altitude at 8:50 am. There were no May day signals or sounds of a struggle. There were no reports from fight attendants. There were voice recorders, bodies or other evidence recovered from the debris. So what we know is based on a single passenger's report.

Barbara Olson, seated in the rear cabin, used her cell phone to twice call her husband, Theodore Olson, the Solicitor General of the United States. According to Solicitor General Olson, she said that the plane had been hijacked, all the passengers were in the back of the plane and that the hijackers in this section had knives and cardboard cutters (or box cutters).

Here is what we do not know:

1)How did the fifth hijacker get aboard?

The FBI found tickets and reservations for four hijackers. The fifth hijacker, Hani Hanjour, according to the Washington Post, was not on the flight manifest. There is also no record of a reservation or ticket. If so, how did he get aboard?

2) What weapons did they hijackers have?

Olson reports the hijackers in rear cabin had knives and box-cutters. But the weaponry of the hijackers in the cockpit is not described. They could have had chemical weapons, guns or bombs for all any one knows.*

3) How did these get these weapons through security at Dulles International Airport?

Four of the hijackers had reservations and tickets and presumably went through the security screening at Dulles. It is not clear where the fifth hijacker, Hani Hanjour, boarded.

4) How did the hijackers gain entry to the cockpits?

None of the pilots had the opportunity to sound a May Day alert or scream. How did the hijackers get through the supposedly locked so as not to alert the pilots?

5) How did the hijackers immobilize the pilots without causing the planes to swerve out of control? The pilots are strapped by harnesses into their seats and have microphones connecting them to ground controllers. How did the hijackers managed to get the pilots out of their seats and take over the controls?

6) Was the planes on auto pilot? If so, how did the hijackers determine this prior to the attack?