Disclosed are methods of forming three dimensional arrays of aligned nanofibers in an open, loose structure of any desired depth. The arrays are formed according to an electrospinning process utilizing two parallel conducting plates to align the fibers and rotating tracks to distribute the fibers throughout the array. Arrays can be used as formed, for instance in tissue engineering applications as three dimensional scaffolding constructs. As-formed arrays can be combined with other materials to form a composite 3-D structure. For instance, composite polymeric materials can be electrospun to form composite nanofibers within the array. Multiple polymeric materials can be electrospun at different areas of the array to form a composite array including materially different nanofibers throughout the array. The arrays can be loaded with other fibrous or non-fibrous materials to form a composite array. Arrays can also be rolled to form a uniaxial fiber bundle
