In many cases, you get different sounds, depending on whether the ship contains a good person or a bad person. (See Star Wars for a particularly good example --> the empire's one-man fighters make an annoying screech sound, whereas the rebellion's figthers make cool swooshing sounds.)
Any aspects of relativity that prevents fast-paced battle scenes and/or stories of galactic empires are ignored. The most obvious example is faster-than-light travel. Also, relativistic effects such as time dilation and length contraction are ignored --> they would complicate the plot too much. (See "Relativity:Distance & Time" drill #1 for an example.)
Here, we are referring to radio transmissions that allow real-time communications between two people separated by several hundred light years. (Radio waves and light waves are the same thing, except for that radio waves have larger wavelengths. They both travel at the speed of light.)
Specifically: even in the vacuum of space, a ship's engines must work hard to keep the ship moving with constant velocity; if the engines fail, the ship comes to a "complete stop."
I'm referring to a particular episode of ST:Voyager, in which the ship gets trapped inside the event horizon of a black hole (the theoretical radius where the gravitational field is so strong that even light cannot escape). Rather than getting crushed to a fruit-juicy pulp, the crew "punches a hole in the event horizon" and flies the ship out.
Disclaimer: This list is not meant as an attack on sci-fi shows. I happen to be a big Sci-fi fan, particularly of the Star Wars movies and of Star Trek in all of its incarnations. Just like Coyote/Road Runner cartoons, they are great entertainment, even if (and, in some cases, because) they take liberties with the known laws of physics.