What are you going to doabout vehicles that can stand the forces of interstellar travel?
Who says they’re interstellar?
Based on our primitive knowledge of physics and the universe, such travel is an impossibility.
But keep in mind, 122 years ago when the Wright Brothers flew the first plane at Kitty Hawk, sending a rocket to the moon was also unheard of and an impossibility.
If there is another race somewhere in the universe, it's reasonable to expect that they could be thousands of years more advanced than us and have redefined all the known laws of engineering and physics.