Some years back, having missed my flight ( in a conventional airliner) I ended up with about twelve hours to sit around before the next connection, so I had a look for something to read. I ended up buying a book of tales from alleged abductees, not one of whom could produce a reasonable account of what happened to them that made any sense at all.
I am fairly certain the vast majority of them were attention seekers and one or two of them were genuinely ill and in need of therapy of some description.
I wish I could remember the title but is was a dozen years ago and I left the book on the seat when my flight was called.
I think life of some kind is highly likely somewhere out there but any life form that is advanced enough to have a practical form of interstellar transport will almost certainly not need to creep around the skies of Earth flashing lights and pissing off jet pilots.
As for the 'We are not ready for them' meme, a good percentage of humanity is still unprepared for walking upright.