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.