No, not quite. (At least to my mind) To me, the definition of a science fiction movie is: a story which takes place within a plausible
technical background. The reason I didn't mention Trek or Star Wars in my listing is because they both use impossiblity layered upon impossibility. (warp drive, transporters, light sabers, disintigrations without residue, huge numbers of alien species able to live within an earth-like enviroment, psychic powers) I also didn't inlcude giant bugs or Godzilla-type films because of the square cube law. These sorts of things make them into fantasy. Nothing wrong with that, mind you... but by my definition, Star Trek is about as realistic as Harry Potter.
There was a great cartoon by Phil Foglio... it was called "the difference between fantasy and science fiction" In one panel, we see a wizard defeating a dragon, who then explains the origin of the wand he used. The explaination goes on for about a half a page, detailing his quest to find it, what favors he had to do to get clues to it's location, and the various monsters and despotic rulers he had to outsmart to finally lay his hands on it.
In the second panel, we see a space hero zapping a huge, dragon-like alien monster. He explains his weapon's origin: "Sears, $19.95"
There's a lot of truth to that.