Right after FBI seized Tesla inventions, the blueprint of electrogravity followed from his inventions. Gravity is essentially electrostatic force and that's a reason why "anti-gravity" propulsion technologies nothing but distortion of space-time with strong electromagnetic field with charges and currents. Philadelphia experiment is another example.

BTW that website plus wikipedia are disinfos, it is not due to atmospheric gaseous electrically charged buoyant plasmas, hallucinations, that's obvious .