File photo of the second tower of the World Trade Center bursting into flames after being hit by an airplane in New York
The second tower of the World Trade Center bursts into flames after being hit by a hijacked airplane in New York in this September 11, 2001 file photograph. Reuters

The World Trade Center and the Pentagon had already been struck when newly minted fighter pilot Lt. Heather Lucky Penney took to the sky on the morning of 9/11, determined to bring down a fourth plane that was hurtling toward Washington, D.C.

But in the scramble to respond to the unexpected assault, Penney had not had time to arm her plane with any ammunition or missiles. As Penney and her wing mate, Col. Marc Sasseville, flew northwest from Andrews Air Force Base, she had a directive that flight school had never prepared her for.

We wouldn't be shooting it down. We'd be ramming the aircraft, Penney told The Washington Post. I would essentially be a kamikaze pilot.

The suicide maneuver didn't end up being necessary, as the passengers of United Airlines Flight 93 famously managed to overwhelm their hijackers and force them to crash the plane into a field in Pennsylvania. Penney and Sasseville aborted the mission, and Penney later flew a plane that escorted a suddenly very vulnerable-feeling Air Force One.

The real heroes are the passengers on Flight 93 who were willing to sacrifice themselves, Penney told the Post. I was just an accidental witness to history.