The present invention provides methods for uniform growth of nanostructures such as nanotubes (e.g., carbon nanotubes) on the surface of a substrate, wherein the long axes of the nanostructures may be substantially aligned. The nanostructures may be further processed for use in various applications, such as composite materials. The present invention also provides systems and methods for growth of nanostructures, including batch processes and continuous processes. For example, in certain embodiments, a system for growing nanostructures is provided which includes a growth substrate, a region able to expose the surface of the growth substrate to a set of conditions selected to cause catalytic formation of nanostructures on the surface of the growth substrate, and a region able to expose the surface of the growth substrate to a set of conditions selected to remove nanostructures from the surface of the growth substrate.