Abstract: The low-altitude economy and urban air mobility have emerged as major areas of interest, while drone-based express delivery and logistics are gradually entering urban operations. These activities will substantially reshape the structure of urban low-altitude airspace, affect its safety, efficiency, and capacity, and exert far-reaching impacts on the form, use, and governance of urban space. The three-dimensional development of future cities will no longer be confined to ground, above-ground, and underground layers; low-altitude airspace will become a fourth layer within a more complete spatial system. This trend introduces new questions and challenges for urban planning. It is therefore necessary to examine the implications of drone deployment through the relationship between airspace and urban space, review relevant international cases, and synthesize planning approaches for drone-oriented urban low-altitude airspace. The findings provide a reference for innovation in urban planning in China.