Here are 10 of the greatest mysteries in aviation, from the early history of flight to modern day.
1. Amelia Earhart
A photograph discovered last year was said to prove that Amelia Earhart did not die in a plane crash but was captured by the Japanese, experts claimed 80 years after her disappearance.
The pioneering aviator vanished over the Pacific Ocean in 1937 while attempting to circumnavigate the globe. Various reasons have been given for her disappearance. The theory that she was captured by Japanese forces has been suggested before; others believe she faked her own death; a few oddballs even claim she was abducted by aliens. The photo, found in a former "top secret" file at the US National Archives, and thought to have been taken in 1937, has been subjected to facial-recognition and other forensic testing – and could put the mystery to bed.
A documentary, Amelia Earhart: The Lost Evidence, aired on the History channel, argued that the photograph proves Earhart and her navigator Fred Noonan were picked up by the Japanese military, who believed they were spies, and taken prisoner. It states that the pair crash-landed in the Japanese-held Marshall Islands and proposed that the US government knew of Earhart's whereabouts and did nothing to rescue her. The theory was somewhat disproved, however, after the new image was said to have appeared in a Japanese travel brochure published years before Earhart disappeared.
2. The Bermuda Triangle
The roughly triangular area bounded by Miami, Bermuda and Puerto Rico is where dozens of aircraft and ships are said to have vanished in unusual circumstances, with the disappearances attributed to paranormal or extraterrestrial activity.
Notable incidents include the disappearance of Flight 19, a US Navy bomber, on December 5, 1945, as well as the aircraft sent to search for it; that of a Douglas DC-3 aircraft with 32 people on board in 1948; and a mid-air collision between two US Air Force planes in 1963.
3. "D B Cooper"
Cooper leapt from a Northwest Boeing 727 similar to this. Photo: Alamy
In 1971, an unidentified man travelling under the name of "Dan Cooper" managed to hijack a Boeing 727, extort a $200,000 ransom, and leap from the rear exit on the aircraft (with a parachute), never to be seen again. No conclusive evidence has emerged confirming his true identity or subsequent whereabouts, but FBI investigatiors claimed he would not have survived the jump.
A year after the incident "Cooper vanes" were installed to disable aircraft doors while the landing gear is up.
4. TWA Flight 800
Trans World Airlines Flight 800, a Boeing 747, exploded and crashed into the Atlantic Ocean near East Moriches, New York, on July 17, 1996, resulting in the deaths of all 230 people on board.
While many speculated that terrorists were to blame, no evidence of a criminal act was discovered by the FBI following a 16-month investigation. Others suggested that a US Navy vessel blew up the plane with a missile strike, and that the US Government has since instigated a cover-up.
A report published on August 23, 2000, however, concluded that a short circuit was the most likely cause of the explosion.
5. Uruguayan Air Force Flight 571
On October 13, 1972, a Uruguayan air force plane carrying 40 passengers and five crew members disappeared while crossing the Andes. Seventy-two days later, after everyone on board was presumed dead, 16 survivors emerged. The story of how starvation drove them to eat some of the dead passengers was made into the 1993 film "Alive".
6. Air France Flight 447
In the early hours of June 1, 2009, Air France Flight 447 from Rio de Janeiro to Paris went missing, along with 216 passengers and 12 crew. The Airbus A330-200 disappeared in the middle of the ocean, beyond radar coverage and in darkness. It took a shocked and bewildered Air France six hours to concede its loss and for several days no trace of it was found. Even when wreckage was discovered, the tragedy was no less perplexing. The aircraft had flown through a thunderstorm, but there was no distress signal, and the jet was state-of-the-art, a type that had never before been involved in a fatal accident. The aircraft's black boxes were recovered nearly two years later, at the bottom of the ocean. A final report, published in July 2012, said the accident occurred due to obstruction of the "pitot tubes" due to ice crystals, which caused the auto-pilot to disengage, as well as human error. It later emerged that the pilot had only slept one hour the previous night after a romantic jaunt in Brazil with his girlfriend.
7. Helios Airways Flight 522
On August 14, 2005, air traffic controllers in Greece lost contact with Helios Airways Flight 522, but the plane remained in the holding pattern for Athens Airport for more than an hour. At one point, a Greek fighter jet was scrambled, and spotted the pilot slumped over the controls. Around half an hour later the plane started to descend, crashing into the hills near Grammatiko, killing all 121 passengers and crew (the deadliest air disaster in Greek history). An investigation revealed that a gradual loss of cabin pressure had left the crew incapacitated.
8. Flying Tiger Line Flight 739
On March 16, 1962, a Lockheed L-1049 Super Constellation propliner carrying 93 US soldiers and 3 South Vietnamese, disappeared in clear weather on its way to Clark Air Base in the Philippines, prompting an eight-day search of more than 200,000 square miles. Eye witnesses on a civilian tanker reported seeing an explosion, but no remains were ever found.
9. Egyptair Flight 990
In 1999, Egyptair Flight 990 from New York to Cairo plummeted into the Atlantic Ocean around 60 miles off the US coast. All 217 people died in the crash, but mystery still surrounds its cause. The Egyptian Flight Officer controlling the plane was recorded repeatedly saying "I rely on God" moments before the disaster, and a colleague claimed he crashed the jet as an act of revenge after being reprimanded by the airline for sexual misconduct, but an investigation concluded he did not deliberately cause the accident.
10. BSAA Avro Lancastrian Star Dust
In August 1947, Star Dust, a British South American Airways airliner vanished as it flew between Buenos Aires, Argentina, and Santiago, Chile, via Mendoza. No wreckage was discovered for over 50 years, provoking conspiracy theories about sabotage and abduction by aliens. A Rolls Royce engine and the remains of nine of the eleven victims were eventually found at the foot of a glacier in the Andes.
The Telegraph, London