As Australia searches for Malaysia Airlines flight MH370 in the Indian Ocean, many missing planes have simply never been found.
Some are believed to have crashed into mountains or water in bad weather, while others simply vanished. All remain lost, despite the best efforts of Australian search teams.
The most famous is the Lady Southern Cross, a Altair monoplane, which disappeared over the Andaman Sea, between India and Singapore, in the early hours of November 8, 1935.
Australian aviation pioneer Sir Charles Kingsford Smith and co-pilot Tommy Perthybridge, who were trying to break the England-to-Australia speed record, were lost.
Although a group of fisherman in Myanmar found the plane’s wheel 18 months later, years of searching failed to find any other part of the Lady Southern Cross.
Seven years earlier, New Zealand aviators Lieutenant John Moncrieff and Captain George Hood vanished while attempting the first trans-Tasman crossing.
About 12 hours into the flight, and within 300 kilometres of New Zealand, signals from the plane ceased.
Despite searches, Moncrieff, Hood and their plane had vanished without a trace.
Perhaps the strangest disappearance involved pilot and UFO enthusiast Frederick Valentich in October 1978.
About halfway into Valentich’s flight aboard a Cessna from Melbourne to King Island he reported seeing a strange aircraft above him, but Melbourne air traffic controllers said no other aircraft were in his area.
Minutes later he made another a strange call to base.
“Melbourne, that strange aircraft is hovering on top of me again,” Valentich said.
“It is hovering and it’s not an aircraft.”
Valentich and his plane disappeared and a four-day search of Bass Strait turned up nothing.
A cowl flap from the plane was found near Cape Otway five years later, but despite an official investigation no one knows what really happened.
Planes vanishing over water is one thing, but one plane has been lost somewhere in NSW for almost 33 years.
Pilot Michael Hutchins was flying over the Barrington Tops National Park with four passengers when his Cessna went missing in August 1981.
The weather was extremely cold with howling winds and Hutchins told air traffic controllers the plane had picked up “a fair amount of ice” over the park’s mountain ranges.
In his last transmission Hutchins told the operator the Cessna was “at 5000 (feet)”.
Despite countless searches, including one last year involving 150 people, the bodies of Hutchins and passengers Rhett Bosler, Noel Wildash, Phillip Pembroke and NSW police superintendent Ken Price have never been found.
Light planes disappear from time to time, but in the modern age of globalised connectivity it’s eerie and unprecedented that an entire airliner, with 239 people aboard, could vanish without a trace.