As the Air Force overhauls its nuclear command, control and communications enterprise, an analysis of alternatives starting later this year will explore how to jointly replace the E-4B National Airborne Operations Center and the Navy's smaller E-6B. Four E-4B "Nightwatch" planes, which serve as flying command centers to control nuclear weapons in case of emergencies, are modified Boeing 747s that are shielded from electromagnetic attacks, connect the nation's leaders and seat more than 100 people. Two were damaged by a...