If you add +ua to the POV-Ray command line then the LDView background is ignored and you'll get a transparent png.
Note though that even when rendering with a transparent background, the "background" statement will still control the colour reflected by any transparent parts such as windows or windscreens.
Note though that even when rendering with a transparent background, the "background" statement will still control the colour reflected by any transparent parts such as windows or windscreens.