Large capacitors exert force, it was what began the research of T.T. Brown who proved discs charged to 300-400kV in a vacuum had reduced weight. Then further research began with USAF. In 1954 Boeing had advertisements claiming planes of future with no fuel, wings, unlimited range etc.. then
T.T. Brown's work was hidden in black projects later with USAF and Boeing never used such advertisements and the rest was 'conspiracy theory'.