Going out on a limb here but, to me this has all the hallmarks of a terrorist or dumb sympathiser attack, max disruption, high grade drones, they have not been able to locate it with usual tech, the reports are overstating that it is not terrorist related due to the panic it would cause plus it appears to be too well orchestrated with perhaps multiple operators for it to be a couple of idiots.
I hope I`m wrong because it could have serious implications on many levels, and lets hope the perpetraitors don`t have anything worse planned!!
Try searching "ISIS Have Drones"
Dreadfull day..