IIRC Stuttgart will be part of phase 2, therefore I suggest adding the "Stuttgarter Fernsehturm" broadcast tower, which is an iconic landmark that can be seen from the airport. https://en.wikipedia.org/wiki/Fernsehturm_Stuttgart
There were also several US military installations in Stuttgart during the cold war, with military training grounds close to the town of Böblingen (Camp Panzer Kaserne). https://en.wikipedia.org/wiki/Stuttgart (see chapter "US military in Stuttgart")