"So you Americans have a place within the CONUS, where normal American laws don´t apply? Where the base commander can act like a dictator and the air force through the president is not responsible to anything? What is the legal status of this site (which only officially exists since a few years)?"
The official government response to Area 51 is that "it doesn't exist". A response that has been held up in Supreme Court rulings. As absurd as it may be, how can laws apply in a place that isn't there, especially environmental issues. One well documented case, at least in Las Vegas, involved the premature deaths of several workers as a result of hazardous waste being burned in an open pit! Only 150 miles from Area 51, I am more concerned with the air that I breath, than the aircraft flying around out there. It was even common knowledge around Las Vegas that there was a stealth fighter a year before it was formally announced to a surprised public!
One way the government can distance itself from Area 51, is through a company known as E.G.& G. Through outsourcing/contracting, it is E.G. & G. that runs Area 51, provides the employees, operates the Janet flights, operates the dozens of busses that leave Las Vegas around 5am delivering workers to the site. I doubt a TWA flight had an emergency landing there. AFAIK, airfield information does not exist on any navigation charts. The restricted area, yes, the airfield, no. Therefore, you would not even know where the airfield is, much less be given clearance to land. Remember "Use of Deadly Force Authorized". Besides, the are other airfields available for emergency diversions.
With the popularity of the movie "Independence Day", it brought a world knowledge to the existence of a supposedly Area 51. Because of this, it has been reported that many programs/projects have been relocated to an area near the Toella Army Depot in Utah, not far from Salt Lake City. As with the site in Nevada, this offers much government land and dry lake beds. As an aside, Toella is also the storage site to every known germ and disease known to mankind.
No doubt, it is an interesting place. Such a place will always exist somewhere.
If not now, then when?