This document discusses the U.S. Air Force's use of an Other Transaction Authority (OTA) to promote open systems acquisition and innovation. It provides an overview of the OTA, including that it allows the Air Force to prototype C4ISR systems using modular, plug-and-play technologies. It describes considerations for the Air Force's C4ISR OTA, such as requiring participation of non-traditional defense contractors. It also discusses plugtests, which allow multiple industry partners to demonstrate initial prototypes for assessment without traditional acquisition red tape. Contact information is provided for those interested in participating or obtaining more information.