September 19, 2001 and After: Media Reports Suggest There Were Plans to Hijack Additional Flights on 9/11

The FBI claims on this day that there were six hijacking teams on the morning of 9/11. [New York Times, 9/19/2001; Guardian, 10/13/2001] A different report claims investigators are privately saying eight. [Independent, 9/25/2001] However, the reports below suggest there may have been as many as nine aborted flights, leading to a potential total of 13 hijackings:
Knives of the same type used in the successful hijackings were found taped to the backs of fold-down trays on a Continental Airlines flight from Newark. [Guardian, 9/19/2001]
The FBI is investigating American Airlines Flight 43, which was scheduled to leave Boston about 8:10 a.m. bound for Los Angeles but was canceled minutes before takeoff due to a mechanical problem. [BBC, 9/18/2001; Chicago Tribune, 9/18/2001; Guardian, 9/19/2001] Another version claims the flight left from Newark and made it as far as Cincinnati before being grounded in the nationwide air ban. [New York Times, 9/19/2001]
Knives and box cutters were found on two separate canceled Delta Airlines planes later that day, one leaving Atlanta for Brussels and the other leaving from Boston. [Time, 9/22/2001; Independent, 9/25/2001]
On September 14, two knives were found on an Air Canada flight that would have flown to New York on 9/11 if not for the air ban. [CNN, 10/15/2001]
Two men arrested on 9/11 may have lost their nerve on American Airlines Flight 1729 from Newark to San Antonio via Dallas that was scheduled to depart at 8:50 a.m., and was later forced to land in St. Louis. Alternately, they may have been planning an attack for September 15, 2001. Their names are Mohammed Azmath and Ayub Ali Khan, whose real name according to later reports is Syed Gul Mohammad Shah. [New York Times, 9/19/2001]
There may have been an attempt to hijack United Airlines Flight 23 flying from JFK Airport, New York to Los Angeles around 9:00 a.m. Shortly after 9:00 a.m., United Airlines flight dispatcher Ed Ballinger sent out a warning about the first WTC crash to the flights he was handling (see 9:19 a.m. September 11, 2001). Because of this warning, the crew of Flight 23 told the passengers it had a mechanical problem and immediately returned to the gate. Ballinger was later told by authorities that six men initially wouldn’t get off the plane. When the men finally disembarked, they disappeared into the crowd and never returned. Later, authorities checked their luggage and found copies of the Koran and al-Qaeda instruction sheets. [Associated Press, 9/14/2001; Chicago Daily Herald, 4/14/2004] In mid-2002, a NORAD deputy commander says “we don’t know for sure” if Flight 23 was to have been hijacked. [Globe and Mail, 6/13/2002]
According to anonymous FAA officials, a plane bound for Chicago, home of the Sears Tower, could have been another target for hijacking. The plane landed unexpectedly at the Cleveland airport after the FAA initiated a national ground stop. Four Middle Eastern men had deplaned and left the airport before officials could detain them for questioning. [Freni, 2003, pp. 81]
A box cutter knife was found under a seat cushion on American Airlines Flight 160, a 767 that would have flown from San Diego to New York on the morning of 9/11 but for the air ban. [Chicago Tribune, 9/23/2001]
The FBI is said to be seeking a number of passengers who failed to board the same, rescheduled flights when the grounding order on commercial planes in the US was lifted. [BBC, 9/18/2001] The Independent points out suspicions have been fueled “that staff at US airports may have played an active role in the conspiracy and helped the hijackers to circumvent airport security.” They also note, “It is possible that at least some of the flights that have come under scrutiny were used as decoys, or as fallback targets.” [Independent, 9/25/2001]