The Defense Department has directed officials managing the development of three next-generation weapon system programs to consider energy efficiency as a key part of their designs, a significant step that could pave the way for economic fuel consumption to play a prominent role in planning for future U.S. combat capabilities. Kenneth Krieg, the Pentagon's acquisition executive, on April 10 signed a memo directing a pilot program to evaluate fuel costs in design trades for the Air Force's future long-range strike...