No. The BIble is quite clear that Satan's First Gang - or the Watchers who chose to follow him and lust after women created the Nephilim with human mothers.I agree with this. The Nephilim were a creation that demons both created and possessed.
I see now why you separate the fallen angels in your title. It was confusing at first.
They are trapped inside Earth and were visited by Jesus in spirit mode during the two days his body was in the tomb.
The second gang chose to follow Satan when he was finally banned from heaven. He was allowed in as written in Job 1:6 KJV:
6 Now there was a day when the sons of God came to present themselves before the Lord, and Satan came also among them.
7 And the Lord said unto Satan, Whence comest thou? Then Satan answered the Lord, and said, From going to and fro in the earth, and from walking up and down in it.
Job's torment happened well after The Flood.
Jesus saw Satan cast out - but was that literally or a vison of a future event?
- Luke 10:18: Jesus says, “I saw Satan fall like lightning from heaven” .
Jesus confirmed Satan ruled Earth 2000 years ago.
Revelation 12:3–4. John sees a sign in heaven: “An enormous red dragon with seven heads and ten horns and seven crowns on its heads. Its tail swept a third of the stars out of the sky and flung them to the earth.” John then relates that the dragon was hurled down to the earth and positively identifies it as “that ancient serpent called the devil, or Satan, who leads the whole world astray” (Revelation 12:9). The dragon is not thrown to earth alone, however: “His angels were cast out with him” (verse 9). The angels that are ejected from heaven with Satan we associate with the “third of the stars” that the dragon’s tail swept from heaven to earth in verse 4.'
Question is: was John describing a past or future event?
Either way it is indisputable that the first gang are still imprisoned and there are enough aliens, Bigfoot, ghosts, poltergeists etc etc to support that Earth has a great number of Fallen Angels wandering it.