Why is the first assumption concerning these UAP/UFO sightings that the military keeps having, NOT that they are OBVIOUS nuclear powered UAV's?
Multiple countries have drone technology.
Multiple countries have nuclear technology.
Nuclear propulsion can provide mass acceleration far in excess of what is demonstrated by these "unknown craft".

Seriously, are that many people so braindead, that they'll accept ALIENS as the god damned answer, before the MUCH MORE PLAUSIBLE EXPLANATION, SOMEONE MADE NUCLEAR DRONES?