Well, first of all there's no such thing as time. Time is relevant only in THIS material dimension and for us. If you read what great people have wrote you will see all of them say this (monks of pretty much all religions, awakened people, etc). Then, something you see you interpret based on YOUR past experiences and beliefs which are EXTREMELY LIMITED. It is the reason why people depicted angels as having wings. Angels don't have wings (they are energy and don't have bodies), however they had to make them with wings because in their perception in order to fly/float you had to have wings since only birds flew. Even more, you perceive things translated not just through your mind but also through the knowledge you have subconsciously from the collective mind of all people (there is such a thing). For example somebody once "opened the skies" as it's called and showed me the angels. They kinda looked human and one of them had a body armor like medieval armors but from a nicer material like whiteish gold. I'm pretty sure that's all as screwed up as it gets because i'm pretty sure angels have no body. This is based not just on my opinion but some ascended people's opinion too (that managed to get out of the body or feel the "heavens" and the angels) and there are even books written under the inspiration of angels (e.g.
Metatron Archangel) who themselves say (the angels) "we do not have wings, this is just how people interpreted us".
People are of mainly of 2 types - the religious type who rather believes in angels and God than in aliens, and the other type who rather believes in aliens than angels and God, and many people who are exceptions from these two, of course. Thing is language and connotations given by religion messed up people's perception (and limited it) a lot. So people understand an angel as a guy who is nice/kind/helpful. I guess that would be an explanation of many and it is true just like saying "a flying object is a pigeon" or "a pigeon is a flying object" or something that is true or almost true but is just a very very small part of the truth.
I know for sure I did saw those angels but I am also sure i saw them in the way my mind "pictured" them or the mind of the person showing them to me pictured them.
Now, where the hell am I going with this? Is simple. You can see something and interpret it in YOUR way. You always see through your perspective and in the case of most people that involves massively the past experiences he or she had. Is how the mind works.
Another important aspect is how you define an alien? Does it have to be organic? Intelligent? Self-aware? From the material world? Can it be from a non-material world and have a non material form (like a spirit/soul)? Does it need a ship/UFO or can he travel through his will alone? If it is organic, does it have to look like a human? Technically speaking, since the Sun and probably any star out there and also the planets have a soul (just trust me on this one) then they are aliens by the standard definition of a non-earthly creature. Then you have the angels, demons and other souls who may be (less evolved ones are probably not) self-aware, intelligent etc. but they are not technically from outside earth or from earth because they're not in the material dimension. But then again, any human's soul is simply an incarnation into a material body of such a soul. The moment we die we go back in that other dimension. Some even travel there without having to die through what is called extracorporalization, astral projection, remote viewing. Technically there are differences since in remote viewing and astral projection generally you don't send the whole spirit out and leave the body empty (as in extracorporalization) but just a small part of the spirit and you can remain conscious in the body. In other words those very sensitive perceive both worlds at the same time - that's how some of the real healers can see the aura - the aura is in the energetic dimension while the body is in the material dimension. It is simply a matter of tuning your mind to perceive both. By the way, for those interested, you can actually train to see the aura and feel "stuff". Reiki would probably be the fastest/easiest way.
Now, I never met an alien and i find it even hard to understand what one is, since I have a very very relaxed understanding of things and don't try to limit myself by categorizing things as most people do. I did however met a demon, saw angels, remembered a past life and had an out of the body experience. By the way, demons and angels are the same thing - a spirit/soul/energy/information/whatever - the only difference is angels live generally in a certain environment (called generally heaven/light) and demons live in another environment (hell/darkness). The worst thing you can do is take these terms in the religious way - that way you'd seriously limit yourself. Even worse if you think angels are good and demons are bad in an absolute way. No such thing, that is just an individual's perception not an absolute thing. Also both are required and both will exist because both form the whole. Even more every single human has a spirit which is the Self (he), angels, demons (to balance the angels

and another set of angels/demons for every job/skill/profession he ever had. Anyway won't go into this as there are books written on these topic that explain everything in great detail.
Now that was I think a pretty in-depth presentation of my not-so-simple answer. However, aside from that let me ask you guys something: why the fu*k would you ever consider believing something like that? Why not instead of reading 400 words of crap written by a moron in a newspaper, go and find a bunch of books that put everything together and analyze information since thousands of years ago, across disciplines and religions and evolution stages? That way you would get a much better view (albeit still incomplete) of these things and expand your perception and shatter some limitations too. Knowledge is power and knowledge does not come from articles in newspapers just like you will never grow 2 extra inches on your penis by taking pills or loose weight healthy and fast by reading an ebook titled "how to loose weight healthy and fast". Don't get me wrong, the world is full of scammer "healers" and gurus and masters and in a way that's just like in the IM world where we all know so well we have our own gurus

But if you read enough, use common sense and critical thinking you will expand your understanding, knowledge and culture.