Future Air Force systems must improve their ability to survive (i.e., their survivability). Many have proposed that more stealth technology be used to achieve that goal. Others have suggested that, considering the high cost and maintenance required for stealth technology, increased speed would be a more effective strategy. To help the Air Force address these issues, the National Research Council was asked to investigate combinations of speed and stealth that would provide U.S. aircraft with a high survival capability in the medium term (about 2018) and to identify changes in planned research and development (R&D) to enable such aircraft. This report provides a review of stealth technology development; a discussion of possible future missions and threats; an analysis of the technical feasibility of achieving various levels of stealth and different speeds by 2018 and of relevant near-term R&D needs and priorities; and a discussion of speed and stealth trade-offs in the face of evolving threats.