System integration plays an important role in the aerospace product development, especially in the development of commercial aircraft as a large-scale and complex system. eVTOL vehicle that attracts attention as a new aircraft development program these days is a small and concise system compared to the commercial aircraft. The development of eVTOL vehicle greatly differs from the development of conventional commercial aircraft in various aspects of development. In addition to clarifying its characteristics and differences, the waterfall-agile hybrid development processes suitable for eVTOL vehicle is proposed in this technical note.