Okay. The only real logical way of time travel being possible is if we were to surpass the speed of light which is impossible. I’m no expert but I’m fairly certain light is the fastest traveling thing in our universe. That being said, whether or not aliens turn out to exist, even with their advanced technology I don’t think they could surpass the speed of light either (no offense aliens. please don’t hurt me.) It just seems intangible. Ludicrous for that matter. But that’s the concept that we believe to be aliens. Doing things man can’t.
Even if man did have an accurate theory on how to travel faster than light, before we could progress our technology to be eligible to do so, our sun would’ve exploded and became a white dwarf. On top of that we’d all be dead. No matter how far our technology progresses given the time we have left here, approximately 5 billion years until it disintegrates us or a few billion years later until it literally eats our planet. We’d need assistance from other entities because there is no possibility of sustainable life that we have access to. Secondly, as of now there are not any other planets that support life (maybe mars, but we’re talking about microscopic organisms) However, assuming aliens can be infinitely far away (or close to us without our knowledge) they might have access to planets or stars that are capable of supporting life that we don’t even know about yet. I am aware that we do have knowledge about other planets that are capable of sustaining life, however, it’d be nearly impossible to travel to them with the time we have left. The only real possibility is if we temporarily move to the moon on another planet that can.