Keywords: lockheed constellation lockheedconstellation lockheed prototype blackandwhite monochrome vehicle aircraft airplane outdoor bike black and white The Lockheed "Sky Sentry," the company's proposal for an airborne early warning aircraft; the forerunner of the EC-121. Lockheed Constellation Military Collection Photo Repository: San Diego Air and Space Museum Archive The Lockheed "Sky Sentry," the company's proposal for an airborne early warning aircraft; the forerunner of the EC-121. Lockheed Constellation Military Collection Photo Repository: San Diego Air and Space Museum Archive |