Well, what Lilium is flying is a demonstrator, not a prototype. The difference is that a prototype is close to the final product and test flights can be used in the early phases of the certification path, demonstrator flights cannot. Or to put harsher: all Lillium has is two model aircraft that have close to nothing in common with the 7 seater they are selling.

And one could call it a scam, when tuh product you sell has nothing to do with the product you show (and no, mock-ups at airshows don't count at all), and the product you sell has, so far, no clear timeline until certification. The aerospace version of vaporware. Whether or not it amounts to an actual scam woupd be for courts to decide. Right now it looks a lot like Nikola, without the option to use a hill to fake the product demo.

As a sidenote regarding test flights: last time I checked, those were unmanned, with a demonstrator and not a prototype and no longer than 6 minutes. Which is as far from what serious people in the field call a test flight of it could be. Good for PR and investors so, it looks cool.

Also, one can make everything fly, if you put enough thrust to it. Doesn't mean you have product that can sustain a business.

That prototype/demonstrator (let's not get silly about words here) looks like it's actually flying properly though. Transitions to horizontal and vertical flights and all. They are planning to have the first manned flight end of this year. A scam would be intentionally misleading people about the ability of this thing to fly at all and then grabbing the money and run.

scam would also involve disgruntled investors trying to sue and getting their money back. There have been a few such cases about investors wanting their money back. But the headline is that Lilium is continuing to raise lots of money and making steady progress to getting their products launched. And those court cases seem to be going nowhere so far. The nature of VC funding is of course that things don't always go to plan.

Just because this company isn't satisfying your need for instant success and instead is following an entirely reasonable path to certification, which is slow for any airplane, doesn't mean it's a scam. By that logic anything is a scam until it emerges fully designed and manufactured on the market. That's not how things work in the real world.

This thing has investors, prospective customers with letters of intent, and flying prototypes.

Nikola is actually shipping trucks at this point too. Yes, they got caught with a non driving prototype running downhill and they got punished for that and the CEO might do some jail time for that. But the thing works now and they are selling lots of trucks that actually move cargo around. A scam would have been if the thing proved to be vapor ware. As it turns out, it wasn't. It was just running a bit late.

>A scam would be intentionally misleading people about the ability of this thing to fly at all and then grabbing the money and run.

There's a fine line between a scam and a business plan which bakes in assumptions that are unrealistic.

I haven't been following those, but the GP's question wasn't about any of the things you enumerated.

The big question is: have they demonstrate a loaded plane flying through a useful distance while keeping enough reserve energy for satisfying the safety requirements?

Their videos are very well produced explanations about everything but this. There's some stuff about a few changes that reduce the reserve requirements, but still, I couldn't find anything about range.

While most of them fly just fine, the economics need still to be proven.

That usually comes after certification. Which some of these things are getting close to. I hear Delta is eager to start shuttling passengers from their terminals with Archer. At this point, you can start making some pretty informed statements about operational cost too. Battery life span and cost is a known factor. The cost of electricity is a known factor. There might be some nasty surprises with components, manufacturing, or scaling up production volume of course.

But mostly these things are starting to look like they are getting there.