If true (big "if" emphasized) you gotta think China has several too, Russia has some, Iran has a few, North Korea even probably has one or two. So nobody has figured out how to fly them/reverse engineer them and conquer the world with them yet? China is over there trying to sneak hot air balloons into Montana while Russia is still using outdated tanks to invade a militarily inferior country. That leads me to believe that
nobody has any alien technology. The most logical solution is usually the correct one. Don't make me put this into meme form...