A key technical issue for future Air Force systems is to improve their ability to survive. Increased use of stealth technology is proposed by many to be the major element in efforts to enhance survivability for future systems. Others, however, suggest that the high cost and maintenance required of stealth technology make increased speed potentially more productive. To help address this issue, the Air Force asked the NRC to investigate combinations of speed and stealth that would provide U.S. aircraft with a high survival capability in the 2018 period, and to identify changes in R&D plans to enable such aircraft. This report presents a review of stealth technology development; a discussion of possible future missions and threats; an analysis of the technical feasibility for achieving various levels of stealth and different speeds by 2018 and of relevant near-term R&D needs and priorities; and observations about the utility of speed and stealth trade-offs against evolving threats.