This document provides an overview of small unmanned aircraft systems (sUAS) and the state of their integration into national airspace systems globally. It discusses various regulatory definitions of sUAS and operational limitations like altitude and visual line of sight restrictions. The top challenges to integration are identified as lack of investment, disunity within the industry, perceptions by manned aviation stakeholders, regulators' understanding of the technology, and trying to apply manned aviation standards. While 2013 was proposed as a deadline for full commercial access in the US, full integration remains an ongoing process with many stakeholders and open questions remaining. The document outlines current and potential markets as well as competitive landscapes and pitfalls to consider.