Does anyone remember ...

Does anyone remember a 1950s U.S. film about a giant flying bird-monster like Rodan, but attracted specifically by movement?

The reason I think it's a U.S. film is, I remember a scene where an American teenaged couple decide to go for a car ride despite all the warnings about the monster. Their friends tell them "You'll get yourselves killed," but they drive off anyway, laughing "If the thing comes around, we'll pour salt on his tail!" (I'm not kidding, that's the dialog.) Of course the thing comes around and swoops them up.

I got it into my head that it was a Rodan movie, but obviously it's not the 1956 film, and as far as I can tell there's never been an American Rodan. Does anybody know what film from my youth I'm trying to remember? (Or did I dream the whole thing...)

udontwant2no