alienlover wrote:

Actually you would have to look int fluid physics to understand the
propulsion systems of  UFOS  It uses a force feild type of propulsion.
Try grabbing a book and reading it befor debating the subject.  Paul R
. Hill. Did a great job and his book Unconventional flying objects is
a great work of scientific research in physics that explain the force
feild used. 

http://www.kopes.com/space/kids/waterrocket.htm