http://www.thesun.co.uk/sol/homepage/features/3546515/Hitler...
https://www.google.co.uk/search?q=nazi+Saucers&ie=utf-8&...
yes yes some of these links are very questionable :/ But where the hell do you find information about hese things. Personally I have always had the option that there must be grains of truths in even the oddest conspiry theorys.
tl:dr = nazi's started hte reseach, before the end of WW2 they destoryed most of it to stop the allies getting it. Allies saw it, tried to replicate it and failed badly. The Real tinhatcrew believes that the nazi's that escaped took this research to russia, how has also experimented with saucers.
if i remember correctly the usa could only get them to hover about 12ft off the ground :/