In this paper, we describe the design and analysis of a fixed-wing unmanned aerial-aquatic vehicle. Inspired by prior work in aerobatic post-stall maneuvers for fixed-wing vehicles [1], we explore the feasibility of executing a water-to-air transition with a fixed-wing vehicle using almost entirely commercial off-the-shelf components (excluding the fuselage). To do this, we first propose a conceptual design based on observations about the dominant forces and dimensionless analysis. We then further refine this concept by building a design tool based on simplified models to explore the design space. To verify the results of the design tool, we use a higher fidelity model along with a direct hybrid trajectory optimization approach to show via numerical simulation that the water-to-air transition is feasible. Finally, we successfully test our design experimentally by hand-piloting a prototype vehicle through the water-to-air transition and discuss our approach for replacing the human-pilot with closed-loop control.