We present a methodology for estimating the state of a micro-aerial vehicle (MAV) as it transitions between different operating environments with varying applicable sensors. We ensure that the estimate is smooth and continuous throughout and provide an associated quality measure of the state estimate. The resulting onboard state estimate is directly applied for feedback control. This video shows experimental results of a MAV autonomously flies through indoor and outdoor environments. Work done by Shaojie Shen and Nathan Michael at the GRASP Lab at the University of Pennsylvania.