Ok, when you extract the zipfile and you get the individual aircraft folder and gauges folder, etc. . .are you saying it doesn't also give you the cab file as part of the extract? If it's visible in the zipfile before you extract everything, there's no reason for it to not extract it.
As others have already explained. . .and I'm sure you know this. . .the cab file does not extract. . .it remains, what appears to be a zipfile. That entire file, as is, get's dropped into the gauges folder.