What the heck guys.

The captain of a United Airlines flight that was supposed to depart on the morning of September 11, 2001, believes his plane might have been meant to be part of the terrorist attacks that day. Yeah, a fifth plane.

This is an airline captain saying this – not some basement-dwelling blogger or Dollar Store conspiracy theorist or something.

In a TMZ special called "9/11: The Fifth Plane," Captain Tom Mannello shares his suspicions about his Flight 23, a Boeing 767 scheduled to depart JFK Airport for L.A. at 9 a.m.

According to Mannello, two box cutters were found in the first-class seat pockets of a plane parked next to Flight 23 – which had a tail number one digit off. He thinks that the people behind the attacks may have simply made a mistake and put the box cutters on the wrong plane. But there's more...

Flight attendants on Flight 23 also shared their suspicions about four passengers in first class, including a person dressed in a hijab they believe was actually a man pretending to be a woman.

A cross-dressing Muslim in a hijab? That's not a thing that happens. 🚩

And there was an odd scene that played out in first class with the shady looking individuals:

Four passengers in first class aroused suspicion shortly after they boarded. The flight attendants say one of the passengers was a man disguised as a woman. The purser [first class flight attendant] tells us those passengers did not eat meat, and there were only 2 fruit plates in the galley. She wanted to get more fruit plates so the passengers could eat, and it triggered a heated argument ... with one of the passengers insisting, "We do not want to eat. We don't need food. We want to take off ... We just want to go."

Flight attendant Sandy Thorngren also recalls a man in business class appearing very nervous and sweating profusely, which she noted as quite strange: "It was odd because it was 8 o'clock in the morning, and airplanes are cold anyway, but it was a cool morning."

Captain Mannello says he was about to take off, unaware of what was happening in Manhattan, when air traffic control ordered all flights back to their gates for a mass evacuation.

Then for some unexplainable reason, 20 minutes after passengers and crew members had left the plane, witnesses on the ground saw two uniformed individuals running through the passenger cabin. Authorities later found an opened floor hatch, which led from the cabin to the belly of the plane. Mannello believes the two people might have been searching for the box cutters found on the neighboring plane.

The FBI interviewed the flight attendants and took them to a lineup at the Port Authority to see if they could identify the suspicious first-class passengers. However, Flight 23 wasn't mentioned in the 9/11 Commission's report.

Flight 23's crew thinks they might have faced a similar fate as the four planes that were hijacked and downed on that fateful and awful day.

"There is a good chance that somebody was plotting to try to use our airplane as a weapon of mass destruction," Captain Mannello said.

Here is the trailer for the TMZ special about Flight 23: