I went to McDonnell Aircraft to pick up a new aircraft for my squadron. A good friend who was working in engineering showed me his work area.
It was in a large room the size of two basketball courts chockablock with narrow aisles and desks shoulder to shoulder in rows.
The theory was to put the engineers close enough together that they could take a few steps and communicate with the all the other engineers in their work group, or take a few more steps and communicate with adjacent work groups as necessary.
This was how the F-4 and F-15 were designed in the days before CAD.