Tesla had plans to build a flying saucer flying without external energy and decided to construct a discoidal condenser large enough to push this allowed to fly.
Several researchers in Europe claimed that Tesla and Marconi had secretly built and tested operational antigravity aircraft. Using electrogravitic drives, these experimental aircraft were eventually based out of a secret location in South America.
Allegedly, Nazi Germany got a hold of this technology and produced several antigravity flying saucers of their own. These flying saucers were used by Nazi Germany in its ‘Foo Fighters” and later in more advanced mills.
Tesla’s last patent in 1928 (Nr. 1,655,114), was for a flying machine that resembled both a helicopter and an airplane. (The lost journals of Nikola Tesla)
Later on, the Secret Service of the US seized all of Tesla’s patents to his death “for reasons of national security.”