The cloaking device comes built in most of your mid-game- advanced craft. It's a building material, you do not need to install it. (Or, in the case of Shadowbat and the like, it comes with it pre-installed).
The cloaking device is a vehicle for storytelling, actually, not a functional piece of equipment. All your craft are assumed to have cloaking built-in, either from cloaking device, or from being ridiculous(zeppelin), old as fuck(buckaroo), or indistinguishable from normal civilian craft(airbus/aircar).