I am going to put my case forward as to why I don't believe this is a helicopter. And don't worry, I'm not claiming it's a Sumerian space craft,
but I am 99% sure I know what it is and I will show why. I posted earlier but will try to explain better now that I am home and can post pics. Here
is probably the best screenshot I could get off the 720p version to explain my reasoning.
First off, if a helicopter was this close, I believe you would be able to hear it unless it had some sort of stealth technology (may exist, but
unlikely it would ever be in this location). Secondly I believe the profile doesn't quite fit a helicopter, although it does indeed look like one.
In this pic the tail is slightly blurred, but I believe the tail is too short compared to the overall body to be a conventional chopper. Also, you
never see any lights flashing which would be a requirement in SoCal, where I believe this video was taken.
Now on to my suspected culprit...
These air swimmers have been a popular Christmas gift, and many have inevitably escaped the confines of an indoor area. I believe these
inconspicuous, helium filled 'air swimmers' fit the profile of the object almost perfectly.
Previous posters have stated that they thought they could see the skids of a helicopter. I believe that these are the pectoral fins, as can be seen
in the top pic. I believe others also thought they could see a rotor hub (but not blades?), and I believe that this is merely the sharks dorsal fin.
Also, the shape of the tail of the UFO seems to match the air swimmers tail shape. The dark colour of the shark would also fit the UFO's dark shape
in the dull lighting conditions.
The movement of the UFO appears to be rather strange for a helicopter, as it slowly rotates ending up 'backwards' while travelling almost constantly
in the same direction. Yet this is a movement that is entirely feasible for an inflatable shark drifting in the light wind. An air swimmer would
also be silent, as it seems to be in the OP video.
One could be forgiven for mistaking one of these air swimmers as a helicopter though. Even experienced pilots have mistaken them here in NZ
There I was, just cruising around at about 1500' above Hamilton in a Robin just having an aerial shufti, when I see an object that looks like a
helicopter off in the distance. However, without getting much bigger (i.e. closer) it suddenly whizzes past my left wing... and although it has the
same general shape as a chopper, this thing has fins and a tail instead of rotors.
It's not a helicopter but actually an Air Swimmer Shark!!
Source - Wings Over New Zealand forum
And this wasn't the only time they've been spotted by a pilot.
The first mid-air encounter happened on Boxing Day.
A plane was 10km south of Christchurch at about 600m on a landing approach when it passed within 100m of a shark, said Civil Aviation Authority
spokeswoman Emma Peel.
Fly-away sharks trigger air alerts
I'm willing to listen to anyone who can refute my propositions or propose a more likely alternative. But until then, I'm going with air swimmer