Some business plans face technical hurdles that are daunting, require tremendous funding, and entail enormous risk, and the eVTOL market is one of them.  eVTOL stands for electric vertical take-off and landing, a technology poised to reshape the aircraft industry—sooner or later. 

Advancements in flight: a centuries-long runway

Airplanes have been around for over a century, but people have been dreaming of flying like birds for much longer. Many historians believe that Abbas Ibn Firnas made the first successful unpowered flight in the ninth century using wings constructed of silk and feathers. This means it only took 700 years for the technology and engineering concepts to mature enough for Orville and Wilbur Wright to fly the first successful example of an airplane in 1903.

eVTOL manufacturers face a similar challenge 

While they are not trying to create a new market (as helicopters can fly from an airport to an urban rooftop), eVTOL makers are trying to revolutionize the industry by addressing the market with electrically powered aircraft whose air taxi services are economically available to a much wider market. In fact, the business viability of an eVTOL product depends on a wide market to achieve the scale necessary to justify the investment. In addition, eVTOLs claim to be more environmentally conscious than traditional aircraft (this claim needs to be validated), and some of them are completely autonomous (no pilot). The sheer volume of near-term technical challenges they are attempting to address is so dizzying it causes many industry observers to quip: “not in my lifetime.” 

The price of developing eVTOL technology quickly 

In an article on a company’s insolvency, the author characterized an eVTOL effort as a “moonshot project,” which appears accurate. But, as Elon Musk and SpaceX have demonstrated, virtually all technical challenges can be solved relatively quickly, although the old adage still applies: 

Better, Faster, Cheaper.  Pick any two.  

With eVTOL technical challenges to solve and business risks to mitigate, investors and program participants need to be prepared for the funding required to get one of these projects across the finish line in less time than it took for human flight to go from Firnas to the Wright brothers.

As with many startups involved in moonshot projects, raising enough funding proved difficult for Lilium. Co-founder Daniel Wiegand gave us an idea of what that looked like in an interview last June, stating the company had $205 million in the bank at the time; that meant a runway "throughout this year, but not into the next year and the year after." The company subsequently initiated a $250 million funding round, but clearly that wasn't enough to keep Lilium in the air.

https://newatlas.com/aircraft/evtol-lilium-insolvency/