If anyone anywhere anytime did space travel, they should have been here by now. The Milky Way is small compared to its age and travel times. The Sun has made about twenty orbits around it. The dinosaurs actually lived on Earth when it was on the other side of the galaxy. Either we are alone as a space faring society, or we have company very close by. The most unlikely scenario is that "they" exist but are far between. As if a part of the ocean had no fish.
Interstellar distances and the constant speed of light ensures that space faring civilizations, even colonies with the same origin, cannot be coordinated. When the communication time lag is thousands of years then technology, culture, policy will evolve completely differently. So if anything is out there, then everything is out there. If Stephen Hawkings is afraid of a dangerous type of aliens, he can rest assured that they, if anyone, do exist and that they are nearby. There are nice guys out there too, everyone is out there, they just cannot be similar to each other.
But that logic has no support at all from observations. All life on Earth is related to each other and had the same origin. You and I have some genes in common with every living cell be it a dog, an insect, a fungus or a disease. We are all family since over three billion years. Nothing ever came here to change that. And the ancient surfaces of the Moon and Mars, where we now can find our own small spacecrafts from orbit, show no signs at all of any artificial manipulation. We are definitely alone as a space faring society in the solar system, and we always have been. This in spite of the fact that the Sun has been all around the galaxy many times and has had many different neighbors.
And SETI has showed us that if they exist then they don't like to use radio very much. Nor do they rebuild galaxies or build Dyson spheres around stars. If we do have neighbors, then thankfully they aren't very noisy. Thinking about it, none of them ever was, which is a bit creepy. Like being all alone in a gigantic hotel, like in the movie The Shining. Your mind begins to make up ghosts as company.