We present BitDrones, a toolbox for building interactive real reality 3D displays that use nano-quadcopters as self-levitating tangible building blocks. Our prototype is a first step towards interactive self-levitating programmable matter, in which the user interface is represented using Catomic structures. We discuss three types of BitDrones: PixelDrones, equipped with an RGB LED and a small OLED display; ShapeDrones, augmented with an acrylic mesh spun over a 3D printed frame in a larger geometric shape; and DisplayDrones, fitted with a thin-film 720p touchscreen. We present a number of unimanual and bimanual input techniques, including touch, drag, throw and resize of individual drones and compound models, as well as user interface elements such as self-levitating cone trees, 3D canvases and alert boxes. We describe application scenarios and depict future directions towards creating high-resolution self-levitating programmable matter.