In order to travel through space in such a way that travel does not depend on the speed of light, you have to bend space for the distances, i.e. attain superluminal speed. For something like that, you need to be able to build a warp field. So that it is not the starship that moves, but the ship that moves space by means of this technology, so that it puts this space over itself like a jumper in order to get to the intended destination in 10 seconds instead of 100 years, for example.

In order to curve space in this way and not burn themselves on arrival and burn everything else near the point of arrival, the beings using such technology would presumably not have to be organic beings, but they themselves would have to be non-matter in order to survive this form of locomotion (which bears the question why they would need this form of traveling in the first place). But since life and existence as non-(conventional) matter would have no (humanly tangible) meaning, there would be no purposeful aiming will to reach anyone or anything to do anything. To move space in the way I mentioned, there is no practical application that we as organic earthlings could witness.

So you can only think in conventional terms of locomotion. If you were to move conventionally in space (starship propulsion by means of terrestrial energy sources), in order to tap into such energy sources you would always have to have a planet nearby that could supply you with exactly the right materials that you would need for propulsion and the other supply systems. We can rule out this form of travel. It'd be too ineffective to overcome relevant distances.

As a material species, it would take too long to construct perfect ships and each would fail due to its own lack of knowledge, as chance would interfere. Countless attempts would have to result in failures, and in this endeavour every species would fail, since its ship would be too small and too slow to be able to compensate for trial and error.

Indirectly, however, we can accept this form of movement in space by acknowledging that our Earth is a spaceship. Starting from the thought that the size of this ship already has perfect conditions and systems such as food, oxygen and other resources. A perfect mix of organics and non-organics, constantly changing in conditions.
Since such a huge ship as the Earth is very complex, it is beyond human comprehension, as there can be no physical command bridge capable of steering this complex ship. Because of the numerous events on the ship itself, people are busy with these events. Since it is a generation ship, the present generations have forgotten that they are travelling with the best of all cosmic bodies. Every now and then, some people remember this and cannot help but see some kind of universal joke in it. Not in a grim way, but rather in an exhilarating way. Since there is no reason to escape, there is no reason to fear death.

To flee the earth would only mean that one hopes to find something "better" elsewhere. But what can be better than living and deep wondering here and now?

Aliens, then, who managed to reach us by non-traditional means, can only be beings that we can categorise as spirits or invisibles, as non-materials, so we will never get to see them. Unless we ourselves dissolve and go on a journey that lets us being spirits or ghosts ourselves. This room for speculation can keep one very absorbed.

To impute to aliens the intention of wanting to "dominate" is mere human projection with which to equate our own history of colonisation. Consider the continents of our earth as distant ship quarters, the oceans, the mountains as spaces between these quarters, and everything that inhabits these quarters as the total expression of what we cannot really grasp if we try too hard.

The all-too-hard attempt to explain IT leads in turn to already existing attempts at explanations that only ever refer back to themselves, a permanent spinning in circles. Why? In the defence that we have long since understood that "we" are "it" (already).

As Alan Watts says:

If the human race develops an electronic nervous system outside the bodies of individual people, thus giving us all one mind and one global body, this is almost precisely what has happened in the organization of cells which compose our own bodies. We have already done it.

As to powers of prediction and control, the individual organism has already accomplished these in a measure which must have astounded the neurons when they have first learned the trick. And if we reproduce ourselves in terms of mechanical, plastic and electronic patterns, this is not really new.

Technical progress becomes a way of stalling faster and faster because of the basic illusion that man and nature, the organism and the environment, the controller and the controlled are quite different things.

I can't prove anything I have said but I see no need in doing so. Only the part where I talk about warp technology and the outcome of using it, I read in a scientific paper some time ago.