Only in general shape. Dimensions, internal systems and even the type and gauge of aluminium were different between the C-135 and 707; Boeing had to go back to

Only in general shape. Dimensions, internal systems and even the type and gauge of aluminium were different between the C-135 and 707; Boeing had to go back to the drawing board when Douglas started cutting metal on the DC-8, and the redesign process for the 707 led to a cascade of changes. About 20% of systems and components were common ( such as the cockpit windows ).