There's a great article over at the Weekly Standard on the heroes of Flight 93.

I'm continually drawn to the similarities between Chamberlain's 20th Maine and Flight 93. Chamberlain was asked to hold Little Round Top against horrible odds; the heroes of Flight 93 were asked to take control of the cockpit from armed, professional killers. When they ran out of ammunition, Chamberlain's men fixed bayonets and charged blindly down the hill; the unarmed heroes of Flight 93 had to storm up a small three-foot-wide aisle. Chamberlain's men held their ground and changed the outcome at Gettysburg; the heroes of Flight 93 succeeded and saved the Capitol.

If you'd like to know more about the battle of Gettysburg, read Michael Shaara's "The Killer Angels." It's a great read.