Barry Amundsen (3
Chuck Missler Return of the Nephilim"
Follow this link to a study by Chuck Missler on your exact
subject. He has written a book called "Return of the
Nephilim" and presents evidence that the same kind of mixing
between fallen angel and human seed that took place in
Noah's day to produce giants or Nephilim is prophesied to be
going on in the last days. You are correct that the UFO and
alien phenomenon is likely the fulfilment of these kinds of
activities in our day.