It's important to realize that the angels Peter is talking about are the angels that left their habitation per the Book of Jude, and took wives of the daughters of Adam. Those are the ones that are locked in chains in Tartaroo (Greek for the deepest part of the abyss).
There are still... other angels in Satan's service roaming about today, just as Satan also is still roaming about today (1 Peter 5:8).
And contrary to the 'opinion' of many, the Revelation 12:7-9 war in Heaven between the Archangel Michael and his angels, against Satan and his angels, has not happened yet today. That is an event that will bring Satan and his angels to this earth, literally, in OUR earthly dimension. Old Testament prophecy revealed that Satan's destruction will be UPON this earth.
As of right now, Satan is still allowed to appear before God's Throne and accuse us. When Rev.12:7-9 happens, he will no longer be allowed in Heaven, period. That leaves only ONE OTHER PLACE he can come, and it is into OUR earthly dimension, for there's only two different dimensions of existence written of in God's Word. Satan will NOT... be coming inside some flesh-born man, like a spirit possession. Satan is coming as 'himself', a beautiful cherub, disguised as "angel of light" Apostle Paul said (2 Cor.11).
And those who do NOT believe angels without the need for flesh bodies, can appear here among us upon this earth, those people who think Satan must possess some flesh person to appear here on earth, are especially setup for deception by the coming "strong delusion".