Exposing Falsehoods and Revealing Truths
The boarding of United 93 on 9/11 presents a puzzle in its own right.
There is a manifest and there are boarding passes that show the names of passengers who took the flight.
The flight went to the Midwest and was in the air after the alleged crash in Shanksville.
Investigators found human remains in Shanksville and declared that the remains matched DNA samples given by the passengers' families.
Here are the three most likely possibilities and reasonable doubts as to them: