In this work, we focus on the theoretical modeling and experimental evaluation of absorbing metasurfaces mounted on unmanned aerial vehicles (UAVs) as facilitators for secure wireless communication channels. Specifically, we present a network architecture based on UAV-mounted metasurfaces and conduct a comprehensive analysis of its components. Furthermore, by utilizing physical optics, namely the Fresnel-Kirchhoff diffraction formula, we develop a comprehensive path loss model that accurately calculates the scattering of wavefronts from metasurfaces with arbitrary configurations; this model enables the quantification of path loss and mobility effects, including pointing accuracy, misalignment, and UAV flying stability, for both near- and far-field conditions. Finally, experimental measurements are conducted using a state-of-the-art static absorbing metasurface and a commercial UAV in an anechoic chamber environment and close agreement between theoretical and experimental results, down to the radiative near-field region, is illustrated. Specifically, our findings indicate that absorbing metasurfaces can act as notch filters with minimal impact on pointing and positioning accuracy, exhibiting a 3 dB beamwidth of ±15° compared to ideal static conditions.