Uh for starters, let me describe to you what Area-51 is. Area-51, is an ultra high security U.S. military base. It is not a secret base, because more people worldwide know where this base is due to TV, movies and popular folklore, than any other military base, you can Google over 500,000,000 links on this, so Area-51 IS NOT A SECRET BASE. Since Area-51 is so well known, keeping weapons there that have the ability to change world domination, is illogical, because Area-51 would be invaded or targeted for destruction in a first line attack. Hence these things, are found at Area-52. Now you know.
PS Area-52 is of course not located adjacent to Area-51, but is likely inside a mountain somewhere, as no runways are needed for gravity type craft, or V/STOL aircraft.