For those who like myself need a good, solid, Christian introduction to the UFO phenomenon, I want to recommend a book:
 
Demons in Disguise
by Fred Deruvo
(2010)
 
The author is convinced these so-called aliens are Nephilim demons and fallen angels and promises to address three questions:
 
1) Why are they doing what they are doing?
2) How are they making it happen?
3) What do they hope to accomplish?
 
The book is available at Amazon in Kindle edition for $9.99
 
YBIC,
 
Robert