The area around Berlin is an unexpected choice.
What I like right off the bat are the giant wind turbines you can find to the South [and maybe elsewhere, but those are the ones I've seen]. But that's a personal gut reaction.
The State of Brandenburg that surrounds but does not include Berlin is governed by a decidedly left-of-center coalition government. I do know that Rolls Royce builds big jet engines just outside the city. There's an industrial park adjacent to the putative new airport:
Business Park Berlin
The VW factory that is ramping up to build the ID lies in East Germany too, but Zwickau is located far away in the direction of Bavaria.
Not sure there's a great track record of the State government working together with business to fast-track investment. However, the problems of Berlin's new city airport are definitely to be found on the side of gross mismanagement by the city [that attempted to coordinate construction instead of delegating to specialized companies] - this would hopefully not be a problem for Tesla.
One Horst Lüning is going to go bonkers. I am intrigued and am sure this will help sell a lot of Teslas in Germany. Thought the coastal plains neighboring the Netherlands or Czechia were the prime candidates.