‘Hype is great to build enthusiasm and gain investment. Innovation brings in new ideas and technologies from other domains. But at the end of the day, the laws of physics require good engineering and a solid understanding of the unique challenges of vertical flight to bring the promise of eVTOL aircraft to market and change the world.‘

http://evtol.news/2018/08/30/electric-vtol-is-taking-off-beware-the-hyper-hype-cycle/