Per-VECTS.
Much subtler reference than I was going to contribute. Well done. 
That’s just the handbrake being left on.
Who would want to time travel into aliens, though?
Stop right there. If their history didn’t have cellphones, then they couldn’t have traveled back in time to a past when they did. Maybe they “jumped universes”, but that’s not time travel.
Also note that, according to one of the Hitchhiker’s Guide to the Galaxy books (IIRC), time travel was “invented” in the distant past, as someone who invented it and went back in time taught the people who were already there how to do it.
There ain’t no difference between a flying saucer and a time machine. People get so hung up on specifics they miss out on seeing the whole thing. Take South America for example. In South America, thousands of people go missing every year. Nobody knows where they go, they just, like, disappear. But if you think about it for a minute, you realize something. There had to be a time when there was no people, right? Well where did all these people come from, huh? I’ll tell you where. The future. And where did all these people disappear to? The past? That’s right! And how did they get there? Flying saucers. Which are really…? Yeah, you got it, time machines. I think a lot about this kind of stuff.
Outside of an alien, a book is a man’s best friend. Inside an alien, it’s too dark to read. – attr. Mark Twain
I think we just got a glimpse into the moderator selection process. 
A lot of people don’t realize what’s really going on. They view life as a bunch of unconnected incidents and things. They don’t realize that there’s this, like, lattice of coincidence that lays on top of everything. Give you an example, show you what I mean: suppose you’re thinkin’ about a plate of shrimp. Suddenly someone’ll say, like, “plate,” or “shrimp,” or “plate of shrimp” out of the blue, no explanation. No point in lookin’ for one, either. It’s all part of a cosmic unconsciousness.
And anyone with half a brain cell would invent the latter model.
If future civilizations have time machines, they’re probably too busy going ahead in time to get answers to their problems to bother with the nitwits of our era.
Who wants to hang out around a bunch of people texting and blowing things up?
You eat a lot of acid, Loach, back in the hippie days?
[Indiana Jones] “Time travellers, I hate these guys…” [/Indiana Jones]
That only applies to some models of time travel. Other models permit an “extension vehicle” that is projected back to times before the projecting base exists. Yet other models permit a free-moving vehicle that can travel to any era.
Occam’s razor in two steps:
First, we start with “Eyewitness testimony has been scientifically proven to be unreliable” People both see and remember things incorrectly, even without an intent to deceive anyone. Some are just plain old-fashioned liars.
After that eliminates 99% of sightings, we move onto “We know that top secret military research is ongoing.” Interesting, in fact, that so many UFO theories actually center around known military research. Almost as if there was a connection…
Pretty sure Occam’s razor has now satisfactorily wrapped up the argument.
Too young to be a hippie. But I am the perfect age to think that the OP isn’t asking a serious question but is instead a reference to Repo Man.
You are not alone.
You are not a loan.
Yes, UFO’s are indeed time machines from our future.
They were invented by the Illuminati on the Dark Side of the Moon (which is why the USA was not allowed to have Moon landings) and are piloted by Yetis.
Their purpose is to use Feng Shui to improve our lives.