Jesus said that in the last days it would very much resemble conditions that existed in the days of Noah.
But as the days of Noah were, so shall also the coming of the Son of Man be.
What were the days of Noah like? Well, the most notable event that occurred during Noah's day was the invasion from Heaven by the "sons of God". These sons of God were fallen angels who the Bible says "left their own habitation" and cohabited with earthly women and produced a breed of half human and half angel hybrids called the nephilim. It is very likely that your church and pastor have never mentioned this story, it is one of the most neglected chapters in all the Bible, Genesis 6. It is a tragedy that God gave us this valuable piece of information in the first six chapters of His Book and it is virtually unknown to most Christians. Undoubtedly Satan has done a masterful job of subduing the spread of this important teaching. For a good teaching on this subject visit this site. There is a correlation between this story and the so called UFO phenomenon and for the sake of brevity I would ask you to visit the excellent teachings of Mr. Chuck Missler. In these last days there has been a tremendous increase in UFO sightings and accounts of alien abductions and genetic experimentation. I believe these accounts are not alien but demonic and I believe they are fulfillment of what Jesus said would occur in these days just as it occured in the days of Noah.