Traveling faster than light is realistic so long as the ship itself doesn't exceed that speed. Humans aren't able to move on their own at more than 15 to 18 mph and that's at a dead run. But inside a car, which becomes the local frame, they are virtually motionless. It's the local frame (the car) that moves at 30 or 40 or 80 mph. Same with SC. It compresses space in front of, and expands space behind, the craft creating a bubble. Inside the bubble, the ship is virtually motionless, but the bubble itself is what travels faster than light.
Now, if NASA could just work out how to do this, we would have a realistic interstellar engine.