Before any of this is to be feasible, there has to be a quantum leap in battery technology! Something comparable to going from Vacuum Tubes to Transistors then to ICs. What needed are Batteries that are very small and light and be able to store huge amounts of power! Something the size of a Sport Battery that could produce extremely high power and last for years w/o charging. Also, The Government has reverse-engineered Alien Anti-Grav Technology. That tech needs to be exploited for all powered flight! Orher reversed Alien Tech includes FTL Travel that gets around the problem of Time Dilation! We see this portrayed in Sci Fi such as Star Trek and DUNE.