In 1917 John Van Valkenburg, a Salt Lake City inventor, announced that he had conquered the laws of gravity and had an aircraft that could fly from Salt Lake City to the Pacific Coast and back in a night. It was reported that he had taken it to Washington and then turned it over to the US government for use in the War effort. Then, suddenly, Van Valkenburg found himself on trial.
What was roaming the skies between 1896 and 1915? Were they airships created by some mad and secretive inventor? Mysteriously technologically-advanced airplanes? Ghost blimps from past conflicts? On this 80th anniversary of the crash of the USS Akron, we look at some mysterious flying machines.