Been thinking about this for a while now: If we (the U.S.) loses a fighter plane or reconnaissance vehicle overseas, we are going to make every effort possible to retrieve it, or at the very least make it near-impossible for another nation to reverse-engineer or learn anything from it. So why would a civilization so much more advanced than us that could pretty easily swoop down onto any military installation on the planet in the middle of the night and take it all back, not done so? And have, let’s face it, ALLOWED us to keep and study their dead pilots and reverse-engineer their technology? Seems either they think we’re too stupid and insignificant to learn anything from it, or they simply hold so little value to life to even bother attempting to recover the bodies of their own citizens, and either answer seems terrifying to me.