An intriguing long read that argues most, if not all, of the recently released video "UFO" footage is in fact of surveillance equipment deployed by other nations.
This actually makes perfect sense, and his arguments are thorough and well reasoned. Think of the technology we have available as consumers, and then imagine what resources the military (foreign & otherwise) has access to. Already we have drone swarms - used for lightshows, "fireworks", etc - (YouTube Link: https://www.youtube.com/watch?v=Zh3-Mvrp1Lc) - it's hardly inconceivable that the country that manufactures such wonders would keep a few for themselves and their own purposes.
Which leads me to another idea, that of the "fan hologram". (See examples on YouTube here: https://www.youtube.com/watch?v=gEa7R7BRUj4). Consider that if instead of using a fan - or, curiously enough - a series of 4 fans - the same technology was integrated into the the propellers of a drone. You could then project the illusion of a moving - spaceship or flying saucer. And think - replace the led lights with colored led diode lasers and you could create the illusion of an alien ship far larger than the drone. Focus the lasers inward to create a cone - or outward to create the illusion of a bigger "Mother Ship" - remember "Close Encounters .." and think that the technology exists already, if not to create the spaceships, then to certainly create a very convincing facsimile.
Also consider the possibilities of dynamic light mapping onto chaff or balloons.
The possibilities are limited only by ones imagination.
So, given the technology exists here on earth, in probably a far greater state of realization than I have imagined or described, and you'll see that no extra-terrestrial origins are necessary for any of the more recent "UFO" sightings. What is surprising is how perfectly mundane most of them have been.