I believe that it is more likely that the fallen ones (only a small percent) that took for themselves wives of the daughters of men (Gen 6 and Jude 6) and created the Giants (Nephilim). When these giants died, they became disembodied souls known as demons. Because they were not fully human, but a hybrid with angels, they are not bound as humans are when they die to go to one place or another but become the powers that help their uncle angels to accomplish the will of their leader, Satan. I believe these are the levels of authority spoken of in Eph. 6. Something to pray about and look into.
This is a common belief which seems to stem from that which claims to be the actual book of Enoch, but scripture certainly seems to refute this belief.
Like here, for example:
Luke 8:30
And Jesus asked him, saying, What is thy name? And he said, Legion: because many devils were entered into him.
Luke 8:31
And they besought him that he would not command them to go out into the deep.
The devils or demons begged Jesus to not command them to go out into the deep or into the abyss as it reads in the Greek. This abyss is the same place that is called the bottomless pit throughout the book of Revelation, and it is a place where at least one angel currently is being held, and it is also the place where Satan, another angel, will be bound for 1000 years during the Millennial Reign of Christ.
Abaddon or Apollyon, who is an angel:
Revelation 9:11
And they had a king over them,
which is the angel of the bottomless pit, whose name in the Hebrew tongue
is Abaddon, but in the Greek tongue hath
his name Apollyon.
Satan, who is an angel:
Revelation 20:1
And I saw an angel come down from heaven, having the key of
the bottomless pit and a great chain in his hand.
Revelation 20:2
And he laid hold on the dragon, that old serpent, which is the Devil, and
Satan, and bound him a thousand years,
Revelation 20:3
And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season.
This is the place that the demons did not want Jesus to command them to go, so it's quite likely that they are angelic beings themselves.