TRB's Airport Cooperative Research Program (ACRP) Report 144: Unmanned Aircraft Systems (UAS) at Airports: A Primer provides airports of all sizes with information about unmanned aircraft systems (UAS) and their potential use and impact on airports. The report includes a glossary of key terms, a background on the current state of UAS operations, UAS costs and benefits to airports, regulatory and community considerations, UAS infrastructure and operational considerations, UAS safety and security issues, and more.