Air Force Studies Board & Committee on Air Force and Department of Defense Aerospace Propulsion Needs 
Review of United States Air Force and Department of Defense Aerospace Propulsion Needs [PDF ebook] 

Rocket and air-breathing propulsion systems are the foundation on which planning for future aerospace systems rests. A Review of United States Air Force and Department of Defense Aerospace Propulsion Needs assesses the existing technical base in these areas and examines the future Air Force capabilities the base will be expected to support. This report also defines gaps and recommends where future warfighter capabilities not yet fully defined could be met by current science and technology development plans.