There Was a 5th Plane on 9/11

A 5th plane was targeted by terrorists on 9/11 -- something the government does not want you to know -- so says the pilot, the flight attendants, the airline's dispatcher, and others.

TMZ produced a documentary -- "TMZ Investigates 9/11: The Fifth Plane" -- which is currently on YouTube. The doc described the events on United Flight 23, which was scheduled to take off from JFK at 9:00 AM, with Los Angeles as the final destination.

There were 7 people who raised suspicion on the part of the crew, checking out the cockpit, arguing with a flight attendant not to delay the takeoff over a food issue.

There's hard evidence people were hiding in the hatch of the plane ... only to surface after the plane was evacuated and locked ... presumably looking to recover incriminating evidence.

The FBI secretly interviewed the entire flight crew, and even presented them with a lineup.

Yet Flight 23 became a deep, dark secret ... the government, the FBI, and United Airlines have all been radio silent.