It's the Home of the Black Helicopters
In conspiracy theorist lore, Area 51 is the manufacturing site of the government's infamous black helicopters, which supposedly are used to conduct sinister missions such as spraying clouds of toxic chemicals over suburban neighborhoods. There even have been people who've claimed they've been abducted by government black helicopters and turned over to flying saucer crews for examination, which suggests a link between the extraterrestrials and human elite who are out to forge a one-world government and intermingle the two species. It's great how all of this stuff actually fits together so neatly, isn't it? [sources: Belzer, Lewis].
It turns out, surprisingly, that there may be at least a tiny bit of truth at the bottom of this theory. As the Las Vegas Review-Journal reported in 2011, the radar-evading stealth technology used by the MH-60 Black Hawk helicopters in the raid on Osama bin Laden's compound actually was developed in the early 1990s at Area 51 [source: Rogers].
Additionally, Area 51 has tested other aircraft with amazing abilities. Perhaps the prime example is the SR-71 Blackbird, the Cold War spy plane, which regularly exceeded speeds of 2,000 mph (3,220 kph) at a height of 80,000 feet (24,390 meters) [source: Hsu].