<p>Cooperative control technology has propelled the development of unmanned surface vessel and unmanned aerial vehicle (USV-UAV) systems. To extend their application potential in complex environments, it is essential to improve the flexibility and robustness of time-varying formation tracking (TFT) control for USV-UAV systems. This article proposes a distributed adaptive TFT control scheme with the output regulation theory, such that all vehicles can realize the expected time-varying formation while tracking multiple leaders. First, a distributed observer is constructed to estimate the global states of all leaders. Subsequently, an adaptive TFT controller is presented for each vehicle based on the output regulation framework and the estimated states of the leaders. Given the external disturbances and unknown nonlinearities, system robustness is effectively enhanced by introducing adaptive parameters and compensation inputs. Additionally, extra formation compensation terms are incorporated into the controller to ensure system adaptability to time-varying formation changes. Finally, theoretical analysis and numerical simulations are presented to demonstrate the effectiveness of the proposed scheme.</p>