I have to start with the definition of the word alien / extraterrestrial.
The word alien coined in the 1950s to mean a being from space with the release of Orson Welles's HG Wells War of the World movie.
The word extraterrestrial meaning being from outside of Earth became popular in the 1950s also.
Considering the meaning of the words extraterrestrial / alien God the Angels even the devil are extraterrestrial beings because none of them are made from anything of the Earth, were born on the Earth, are from the Earth. All are from outside of the Earth the kingdoms in which they live is somewhere out there in space.
Jesus said my kingdom is not of this *world*
Now it's hard for many Christians too look upon them in such manner but the truth is they are extraterrestrial beings - nor does it take away from the Divinity of Our Lord.
What has occurred in the past and what is occurring in the present actually substantiate his existence.
Reading the Bible as it is written, the Bible is full of extraterrestrial beings from beginning to end.
What is Ezekiel's Wheels and what are the cherubims that were with them?
The chariots of God what are they?
https://bible.knowing-jesus.com/topics/Heavenly-Chariots
Many angels are described as having a extreme brightness about them - so are the crafts of today.
Many of the Angels are described as having extremely great speed - so are the crafts of today.
Angels have been described as being invisible to the naked eye unless God opens one eye to see - eyewitnesses of today have witnessed crafts appearing and disappearing.
And what exactly are the wings of an Angel could it just be how the ancients describe something that they couldn't figure out how to describe. Wings indicate the capability of flight.....
Enoch and Elijah taken up (today would be considered abduction) - Jesus ascended up.
Some think they are demons or nephilims, well if they have these type of crafts then the angels in heaven have these type of crafts Too.
I personally think they are angels of Our Lord _ Watchers watching as they did in the Old Testament and have been doing throughout the lifespan of mankind.
Some very old Christian paintings that depicts UFOs
https://sports.yahoo.com/ufos-discovered-historical-paintings-114905870.html
https://www.indiatimes.com/trending/wtf/1000-year-old-jesus-painting-has-ufo-603924.html