Recently, the European Aviation Safety Agency and other civil aviation authorities introduced a regulatory framework for low- and medium-risk operations of unmanned aerial systems (UAS) where medium-risk operations fall into the ‘specific’ category. Other introduced categories are the ‘open’ category for very-low-risk operations and the ‘certified’ category for high-risk operations that are comparable to manned aviation. This framework has the potential to reduce the certification costs compared to manned civil aviation. This paper discusses the challenges for operators of high-altitude platforms who aim for medium-risk UAS operations in the ‘specific’ category. It also shows ways to obtain an operation approval in the ‘specific’ category and how to deal with the associated operational requirements to perform such long-endurance UAS missions. Moreover, problems the high-altitude platform operator has to face when applying SORA are discussed. The paper closes with a promising approach to further enable high-altitude operations and to face some of the problems that occurred in the applicability of SORA to high-altitude platform operations by the use of 4D-operational volumes and unmanned traffic management (UTM) services.