Since Hamburg joined the UAM Initiative Cities Community (UIC2) of the European Union’s (EU) Smart Cities Marketplace as one of the first European cities back in 2018, it has achieved important breakthroughs but also faced challenges that clearly indicate the stony path towards a functional and accepted integration of UAV into the existing traffic system and urban airspace, write Daniela Richter, Project Lead Blue-Space at Hamburg Aviation, and Karlotta Victor, Legal Researcher on UTM at the Air Traffic Department of the Ministry for Economics and Innovation, Hamburg. (....)