In fish tank VR environments, the screen is used as a window into a virtual environment. This effectively creates a useful 3D workspace in the vicinity of the monitor screen, near to the user. However, many geographical applications require the user to cover large virtual distances and to support this a flying interface is often provided. The authors describe a method for combining the flying and fish tank metaphors to create a practical working environment. The central insight developed in the paper is that a geometric transformation that they call the "cyclopean scale" enables the simple combination of flying and fish tank VR interaction metaphors. Cyclopean scale continuously scales the working environment to lie just behind the screen in terms of stereoscopic depth. Cyclopean scale allows for fish tank VR viewing and also places objects at a convenient distance for manipulation, optimizes stereo display parameters and reduces stereo display problems (vergence focus conflict). They have implemented this technique in a system called Fledermaus VR with a cable route editing task. This is an application for planning the layout of submarine cables.