Boeing plane was stolen from airport in 2003 but no one knows what happened to it after that

Missing plane conspiracies are scary enough to make you never want to fly again.

Case in point - the mysterious case of the missing Angola Boeing 727 that disappeared in 2003.

What sets this case apart is the fact that the aircraft was stolen from the airport.

And it has still yet to be found twenty years on.

A Boeing 727 (not pictured) went missing in 2003. (Ralf-Finn Hestoft/CORBIS/Corbis via Getty Images)

Two men boarded the plane on May 25, 2003, as it sat parked in Aeroporto Quatro de Fevereiro in Luanda, Angola.

One man, Ben C. Padilla was a US citizen and a private pilot, whilst the other, John M. Mutantu was from Angola.

The plane, whose plane number read 844AA, was old, having accumulated 68,488 hours in the sky and 43,390 cycles over 26.5 years - but was considered to be in working order.

However, back in 2003, planes didn't have the same tracking technology that they have today.

After takeoff, the men then switched off the lights and the transponder and the plane has not been seen since - having last been seen heading south-west towards the Atlantic Ocean.

The plane disappeared without a trace. (Getty stock image)

The aircraft, which, according to Aviation Safety Network, was owned by Aerospace Sales & Leasing, had been grounded at the airport since March 2002.

According to Simpleflying.com, the plane was reportedly in the process of being converted for use by Nigerian company IRS Airlines.

So, that's all the background...what are the theories?

Padilla's sister, Benita Padilla-Kirkland, has her own.

Speaking to the South Florida Sun-Sentinel in 2004, she voiced her suspicions that the plane had either crashed somewhere in Africa or her brother was being held against his will.

And Padilla's brother, Joe, had a similar working theory.

Speaking in 2010, he maintained that somebody had been waiting on the plane for Padilla and Mutantu.

He also believed that they were forced into taking the aircraft and then killed.

Other theories include that the plane crashed into the Atlantic Ocean, stolen for insurance fraud or that it was disassembled for parts on the Tanzania border.

No plane debris has ever been found. (Getty stock image)

At the time, retired US Marine General and the commander of US forces in the Horn of Africa, Mastin Robeson, said: "It was never clear whether it was stolen for insurance purposes by the owners, whether it was stolen with the intent to make it available to unsavory characters, or whether it was a deliberate, concerted terrorist attempt.

"There was speculation of all three."

A sighting was initially reported in July 2003 in Conarky, Guinea, but later dismissed by the U.S. State Department.

The mystery of the plane remains unsolved - with a 2010 deep-dive investigation published in Smithsonian Magazine drawing out no conclusive answers.

The author, Tim Wright, finished the article on this note, saying: "I found a story of broken deals, disappointments, and betrayals, but no real clues to the aircraft’s destination that day in 2003.

"We may never know for sure where it went. It is the largest aircraft ever to have disappeared without a trace."

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