Planview air traffic displays depict latitude and longitude of aircraft graphically via display position but depict altitude alphanumerically via data tags. Operators must integrate both graphical and alphanumeric information to generate mental models of air traffic, perhaps limiting performance. Palmer, Clausner & Kellman (2008) showed that aircraft icons with altitude-correlated size and contrast improved detection of potential collisions. These cues may have been effective because they corresponded to the depth cues of relative size and aerial perspective, thus providing naturalistic visual metaphors for interpreting the displays. Here, we varied whether icons were correlated with depth or not and also whether observers assumed a from-above or from-below viewing perspective. In Experiment 1, the from-above perspective with depth-consistent icons yielded better performance than the from-below perspective with depth-inconsistent icons, despite these displays being physically identical. Experiment 2 replicated the finding and showed that contrast/grayscale variations evoke the perspective effect but color variations do not.