Maybe for some small period of time, but not for long. Americans, and I think people in general, can be quite adaptive. In Texas enough people would just start carrying around shotguns for the chance to be the one to shoot it out of the sky. In San Francisco, who knows, maybe some counter drone tech would be quickly developed. A large society can absorb hundreds of deaths a day without too many problems if it knows the problem is not going to escalate exponentially.