Kitbashing is a term coined in the cinematic miniature (the art of making miniatures for visual effects) world. It generally means buying pre-formed models (such as model airplanes made of plastic to be displayed on a shelf), taking parts from that kit, and combining it with others (or your own custom parts) to create something new. For instance, you can see parts of the original Star Wars Millenium Falcon that include guns and exhausts from various military model kits.
Some purists may think of this as cheating. They are amateurs. Professionals do it all the time. After all, where time is money, why reinvent something that already exists?
Throughout this book, we're going to use the same philosophy. We're going to take dumb objects and make them smart with the Pixhawk controller and components. On some projects, we'll even go full-kitbashing by combining two or more objects into one smart object.