Interaction techniques that utilize the space above the display surface to extend the functionalities of digitized surfaces continue to emerge. In such techniques, movements are constrained by the bounds of a layer. In addition, constraints imposed on the direction of movement within the layer may be present. Despite the presence of such techniques, there is limited understanding of human capabilities for performing the required steering task. In this paper we study and model user performance when steering through constrained and unconstrained paths in above-thesurface layers. Through a series of experiments we validate the derivation and applicability of our proposed models.