Behavior-based robotic systems have been successfully deployed for a wide range of planar ground-based tasks. This article describes how reactive (behavior-based) systems can be applied to new and more difficult target domains. ln particular, schema-based navigation is shown to be both feasible and useful in two new areas: three-dimensional navigation for use in aerospace and undersea applications, and "two and one-half"-dimensional surroundings for outdoor navigation in rough terrain. Extensive simulation studies demonstrate the utility of this approach in both cases.