Have you heard about the airliner which was ordered back to the gate on 9/11 when the terrorist attacks began, only to have four young Arab passengers jump off the plane, after which box cutters and Al Qaeda documents were found in their abandoned bags?

I’ve heard that story before, but since it was never reported by the U.S. government, and not mentioned by the 9/11 Commission in their official report, I thought it might be another of those urban myths. Until now.

Yesterday’s Wilmington (Delaware) News-Journal featured a front-page article on the Delaware Air National Guard’s first female general, Carol Timmons, who was promoted to that rank at a ceremony on Saturday. General Timmons has had a long career as a pilot, including time as a commercial pilot for Pan Am and United Airlines.

The profile of General Timmons recounts that on the morning of September 11, 2001, she was the first officer on United Airlines flight 23 preparing to take-off from New York’s JFK Airport bound for Los Angeles. The plane had already pulled away from the gate and was taxiing down the runway when the airport was shut down and the crew was ordered to secure the cockpit.

Timmons confirmed that as the pilot grabbed the crash ax, she jumped from her seat and started barricading the cockpit door. From the other side of the barricade the cabin crew relayed their concern about four young Arab men in first-class who became agitated when the take-off was cancelled, and fled from the plane when it returned to the terminal. Box cutters and Al Qaeda documents were later found in their luggage.

Timmons, the pilot, and the rest of the crew were repeatedly questioned by the FBI, though the findings were never shared. The pilot concluded that Flight 23 would have been the next plane hijacked by terrorists if the airport shutdown order had been delayed.

“The FBI asks questions,” General Timmons is quoted as saying, “They don’t tell you things.”

Why wouldn’t the U.S. government want to report the incident? Why didn’t the 9/11 Commission mention it in their official report? Were they concerned about panicking the public? Were they trying to apprehend the four passengers who fled? Why maintain official silence about the incident a decade later?